Document:

[Bank of America, N.A. Letterhead]

May 19, 2000

Mariner Energy, Inc.
580 WestLake Park Blvd., Suite 1300
Houston, Texas  77079

Gentlemen:

     Reference is made to that certain Amended and Restated Credit Agreement
dated June 28, 1999 among Mariner Energy, Inc., a Delaware corporation
("Borrower"), Bank of America, N.A. (fka NationsBank, N.A.), a national banking
association, as Administrative Agent (the "Agent") and Bank of America, N.A.
(fka NationsBank, N.A.), as amended by that certain First Amendment to Amended
and Restated Credit Agreement dated December 31, 1999, among Borrower, Agent,
Toronto Dominion (Texas), Inc., as Co-Agent ("Co-Agent") and the financial
institutions listed on Schedule 1 thereto (the "Banks"). Said Amended and
Restated Credit Agreement, as amended by said First Amendment to Amended and
Restated Credit Agreement, is referred to herein as the "Credit Agreement".
Capitalized terms used herein but not otherwise defined herein shall have the
respective meanings given thereto in the Credit Agreement.

     Pursuant to the provisions, procedures and standards set forth in Section
4.2 of the Credit Agreement, Agent has determined that, from and after the date
of this letter until a new Borrowing Base has been approved in accordance with
the requirements of the Credit Agreement, the Borrowing Base shall be
$70,000,000.00. Agent has received the approval by all Banks of the change in
the Borrowing Base described herein.

     Except for the change in the Borrowing Base described herein, the Credit
Agreement shall remain unchanged, and the terms, conditions and covenants of the
Credit Agreement shall continue and be binding upon Borrower, Agent, Co-Agent
and the Banks.

     THE CREDIT AGREEMENT, AS MODIFIED BY THIS LETTER, REPRESENTS THE FINAL
AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

     THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

     To evidence your agreement to the foregoing, please execute in the space
designated below.

                              BANK OF AMERICA, N.A., as Administrative Agent

                              /s/ James V. Ducote
                              ---------------------------------
                                 James V. Ducote
                                 Vice President

ACKNOWLEDGED AND AGREED TO:

MARINER ENERGY, INC.

/s/ Frank A. Pici
---------------------------------
   Name:  Frank A. Pici
   Title: VP of Finance & CFO<PAGE>   1
                                                                     EXHIBIT 4.1

                     INDENTURE DATED AS OF NOVEMBER 1, 2000
           ----------------------------------------------------------

                                 ALLERGAN, INC.

                          Liquid Yield Option(TM) Notes
                                    due 2020
                           (Zero Coupon-Subordinated)
           ----------------------------------------------------------

                                    INDENTURE

                          Dated as of November 1, 2000
           ----------------------------------------------------------

                                 U.S. BANK TRUST
                              NATIONAL ASSOCIATION

                                     TRUSTEE
           ----------------------------------------------------------

                   (TM)Trademark of Merrill Lynch & Co., Inc.

<PAGE>   2

                             CROSS REFERENCE TABLE*
<TABLE>
<CAPTION>

<S>                                                        <C>
IA Section...........................................      Indenture Section
310(a)(1)............................................             7.10
   (a)(2)............................................             7.10
   (a)(3)............................................             N.A.
   (a)(4)............................................             N.A.
   (b)...............................................          7.08; 7.10
   (c)...............................................             N.A.
311(a)...............................................             7.11
   (b)...............................................             7.11
   (c)...............................................             N.A.
312(a)...............................................             2.05
   (b)...............................................            13.03
   (c)...............................................            13.03
313(a)...............................................             7.06
   (b)(1)............................................             N.A.
   (b)(2)............................................             7.06
   (c)...............................................            13.02
   (d)...............................................             7.06
314(a)...............................................      4.02; 4.03; 13.02
   (b)...............................................             N.A.
   (c)(1)............................................            13.04
   (c)(2)............................................            13.04
   (c)(3)............................................             N.A.
   (d)...............................................             N.A.
   (e)...............................................            13.05
   (f)...............................................             N.A.
315(a)...............................................             7.01
   (b)...............................................         7.05; 13.02
   (c)...............................................             7.01
   (d)...............................................             7.01
   (e)...............................................             6.11
316(a) (last sentence)...............................             2.08
   (a)(1)(A).........................................             6.05
   (a)(1)(B).........................................             6.04
   (a)(2)............................................             N.A.
   (b)...............................................             6.07
317(a)(1)............................................             6.08
   (a)(2)............................................             6.09
   (b)...............................................             2.04
318(a)...............................................            13.01

                           N.A. means Not Applicable.
</TABLE>

------------------
*       Note: This Cross Reference Table shall not, for any purpose, be deemed
        to be part of the Indenture.

<PAGE>   3

                               TABLE OF CONTENTS*
<TABLE>
<CAPTION>

                                                                                          PAGE

                     ARTICLE 1 DEFINITIONS AND INCORPORATION BY REFERENCE

  <S>               <C>                                                                   <C>
  SECTION 1.01      Definitions..............................................................1
  SECTION 1.02      Other Definitions........................................................5
  SECTION 1.03      Incorporation by Reference of Trust Indenture Act........................6
  SECTION 1.04      Rules of Construction....................................................7

                            ARTICLE 2 THE SECURITIES

  SECTION 2.01      Form and Dating..........................................................7
  SECTION 2.02      Execution and Authentication.............................................9
  SECTION 2.03      Registrar, Paying Agent and Conversion Agent.............................9
  SECTION 2.04      Paying Agent to Hold Money and Securities in Trust......................10
  SECTION 2.05      Securityholder Lists....................................................10
  SECTION 2.06      Transfer and Exchange...................................................10
  SECTION 2.07      Replacement Securities..................................................12
  SECTION 2.08      Outstanding Securities; Determinations of Holders' Action...............12
  SECTION 2.09      Temporary Securities....................................................13
  SECTION 2.10      Cancellation............................................................13
  SECTION 2.11      Persons Deemed Owners...................................................14
  SECTION 2.12      Global Securities.......................................................14
  SECTION 2.13      CUSIP Numbers...........................................................19

                       ARTICLE 3 REDEMPTION AND PURCHASES

  SECTION 3.01      Right to Redeem; Notices to Trustee.....................................19
  SECTION 3.02      Selection of Securities to Be Redeemed..................................19
  SECTION 3.03      Notice of Redemption....................................................20
  SECTION 3.04      Effect of Notice of Redemption..........................................20
  SECTION 3.05      Deposit of Redemption Price.............................................20
  SECTION 3.06      Securities Redeemed in Part.............................................21
  SECTION 3.07      Conversion Arrangement on Call for Redemption...........................21
  SECTION 3.08      Purchase of Securities at Option of the Holder..........................21
  SECTION 3.09      Purchase of Securities at Option of the Holder upon Change in Control...27
  SECTION 3.10      Effect of Purchase Notice or Change in Control Purchase Notice..........30
  SECTION 3.11      Deposit of Purchase Price or Change in Control Purchase Price...........31
  SECTION 3.12      Securities Purchased in Part............................................31
  SECTION 3.13      Covenant to Comply With Securities Laws Upon Purchase of Securities.....32
  SECTION 3.14      Repayment to the Company................................................32
</TABLE>

--------
*       Note: This Table of Contents shall not, for any purpose, be deemed to be
        part of the Indenture.

                                       i

<PAGE>   4

<TABLE>
<CAPTION>

                               ARTICLE 4 COVENANTS

  <S>               <C>                                                                     <C>
  SECTION 4.01      Payment of Securities...................................................32
  SECTION 4.02      SEC and Other Reports...................................................33
  SECTION 4.03      Compliance Certificate..................................................33
  SECTION 4.04      Further Instruments and Acts............................................33
  SECTION 4.05      Maintenance of Office or Agency.........................................33
  SECTION 4.06      Delivery of Certain Information.........................................34

                         ARTICLE 5 SUCCESSOR CORPORATION

  SECTION 5.01      When Company May Merge or Transfer Assets...............................34

                         ARTICLE 6 DEFAULTS AND REMEDIES

  SECTION 6.01      Events of Default.......................................................35
  SECTION 6.02      Acceleration............................................................37
  SECTION 6.03      Other Remedies..........................................................37
  SECTION 6.04      Waiver of Past Defaults.................................................37
  SECTION 6.05      Control by Majority.....................................................38
  SECTION 6.06      Limitation on Suits.....................................................38
  SECTION 6.07      Rights of Holders to Receive Payment....................................38
  SECTION 6.08      Collection Suit by Trustee..............................................39
  SECTION 6.09      Trustee May File Proofs of Claim........................................39
  SECTION 6.10      Priorities..............................................................39
  SECTION 6.11      Undertaking for Costs...................................................40
  SECTION 6.12      Waiver of Stay, Extension or Usury Laws.................................40

                                ARTICLE 7 TRUSTEE

  SECTION 7.01      Duties of Trustee.......................................................40
  SECTION 7.02      Rights of Trustee.......................................................41
  SECTION 7.03      Individual Rights of Trustee............................................42
  SECTION 7.04      Trustee's Disclaimer....................................................42
  SECTION 7.05      Notice of Defaults......................................................42
  SECTION 7.06      Reports by Trustee to Holders...........................................43
  SECTION 7.07      Compensation and Indemnity..............................................43
  SECTION 7.08      Replacement of Trustee..................................................44
  SECTION 7.09      Successor Trustee by Merger.............................................44
  SECTION 7.10      Eligibility; Disqualification...........................................44
  SECTION 7.11      Preferential Collection of Claims Against Company.......................45

                        ARTICLE 8 DISCHARGE OF INDENTURE

  SECTION 8.01      Discharge of Liability on Securities....................................45
  SECTION 8.02      Repayment to the Company................................................45

                              ARTICLE 9 AMENDMENTS

  SECTION 9.01      Without Consent of Holders..............................................45
  SECTION 9.02      With Consent of Holders.................................................46
</TABLE>

                                       ii
<PAGE>   5

<TABLE>
<CAPTION>

  <S>               <C>                                                                     <C>
  SECTION 9.03      Compliance with Trust Indenture Act.....................................47
  SECTION 9.04      Revocation and Effect of Consents, Waivers and Actions..................47
  SECTION 9.05      Notation on or Exchange of Securities...................................47
  SECTION 9.06      Trustee to Sign Supplemental Indentures.................................47
  SECTION 9.07      Effect of Supplemental Indentures.......................................47

                     ARTICLE 10 SPECIAL TAX EVENT CONVERSION

  SECTION 10.01     Optional Conversion to Semiannual Coupon Note Upon Tax Event............47
  SECTION 10.02     Payment of Interest; Interest Rights Preserved..........................48

                              ARTICLE 11 CONVERSION

  SECTION 11.01     Conversion Privilege....................................................49
  SECTION 11.02     Conversion Procedure....................................................51
  SECTION 11.03     Fractional Shares.......................................................52
  SECTION 11.04     Taxes on Conversion.....................................................52
  SECTION 11.05     Company to Provide Stock................................................52
  SECTION 11.06     Adjustment for Change In Capital Stock..................................52
  SECTION 11.07     Adjustment for Rights Issue.............................................53
  SECTION 11.08     Adjustment for Other Distributions......................................54
  SECTION 11.09     When Adjustment May Be Deferred.........................................56
  SECTION 11.10     When No Adjustment Required.............................................56
  SECTION 11.11     Notice of Adjustment....................................................57
  SECTION 11.12     Voluntary Increase......................................................57
  SECTION 11.13     Notice of Certain Transactions..........................................57
  SECTION 11.14     Reorganization of Company; Special Distributions........................58
  SECTION 11.15     Company Determination Final.............................................58
  SECTION 11.16     Trustee's Adjustment Disclaimer.........................................58
  SECTION 11.17     Simultaneous Adjustments................................................59
  SECTION 11.18     Successive Adjustments..................................................59
  SECTION 11.19     Rights Issued in Respect of Common Stock Issued Upon Conversion.........59

                            ARTICLE 12 SUBORDINATION

  SECTION 12.01     Securities Subordinate to Senior Indebtedness...........................59
  SECTION 12.02     Payment over of Proceeds upon Dissolution, Etc..........................59
  SECTION 12.03     Acceleration of Securities..............................................61
  SECTION 12.04     Default on Senior Indebtedness..........................................61
  SECTION 12.05     Payment Permitted If No Default.........................................62
  SECTION 12.06     Subrogation to Rights of Holders of Senior Indebtedness.................63
  SECTION 12.07     Provisions Solely to Define Relative Rights.............................63
  SECTION 12.08     Trustee to Effectuate Subordination.....................................63
  SECTION 12.09     No Waiver of Subordination Provisions...................................64
  SECTION 12.10     Notice to Trustee.......................................................64
  SECTION 12.11     Reliance on Judicial Order or Certificate of Liquidating Agent..........65
  SECTION 12.12     Trustee Not Fiduciary for Holders of Senior Indebtedness................65
  SECTION 12.13     Rights of Trustee as Holder of Senior Indebtedness; Preservation of
                    Trustee's Rights........................................................65
</TABLE>

                                      iii
<PAGE>   6

<TABLE>
<CAPTION>

  <S>               <C>                                                                     <C>
  SECTION 12.14     Article 12 Applicable to Paying Agents..................................65

                            ARTICLE 13 MISCELLANEOUS

  SECTION 13.01     Trust Indenture Act Controls............................................66
  SECTION 13.02     Notices.................................................................66
  SECTION 13.03     Communication by Holders with Other Holders.............................67
  SECTION 13.04     Certificate and Opinion as to Conditions Precedent......................67
  SECTION 13.05     Statements Required in Certificate or Opinion...........................67
  SECTION 13.06     Separability Clause.....................................................67
  SECTION 13.07     Rules by Trustee, Paying Agent, Conversion Agent and Registrar..........68
  SECTION 13.08     Legal Holidays..........................................................68
  SECTION 13.09     GOVERNING LAW...........................................................68
  SECTION 13.10     No Recourse Against Others..............................................68
  SECTION 13.11     Successors..............................................................68
  SECTION 13.12     Multiple Originals......................................................68
</TABLE>

                                       iv
<PAGE>   7

               INDENTURE dated as of November 1, 2000 between ALLERGAN, INC., a
Delaware corporation ("Company"), and U.S. BANK TRUST NATIONAL ASSOCIATION, a
national banking association organized under the laws of the United States
("Trustee").

               Each party agrees as follows for the benefit of the other party
and for the equal and ratable benefit of the Holders of the Company's Liquid
Yield Option(TM) Notes due 2020 (Zero Coupon - Subordinated) ("Securities"):

                                    ARTICLE 1

                   DEFINITIONS AND INCORPORATION BY REFERENCE

               SECTION 1.01  Definitions

               "144A Global Security" means a permanent Global Security in the
form of the Security attached hereto as Exhibit A-1, and that is deposited with
and registered in the name of the Depositary, representing Securities sold in
reliance on Rule 144A under the Securities Act.

               "Affiliate" of any specified person means any other person
directly or indirectly controlling or controlled by or under direct or indirect
common control with such specified person. For the purposes of this definition,
"control" when used with respect to any specified person means the power to
direct or cause the direction of the management and policies of such person,
directly or indirectly, whether through the ownership of voting securities, by
contract or otherwise; and the terms "controlling" and "controlled" have
meanings correlative to the foregoing.

               "Applicable Procedures" means, with respect to any transfer or
transaction involving a Global Security or beneficial interest therein, the
rules and procedures of the Depositary for such Security, in each case to the
extent applicable to such transaction and as in effect from time to time.

               "Board of Directors" means either the board of directors of the
Company or any duly authorized committee of such board.

               "Business Day" means each day of the year other than a Saturday
or a Sunday on which banking institutions are not required or authorized to
close in the City of New York or Los Angeles, California.

               "Capital Stock" for any corporation means any and all shares,
interests, rights to purchase, warrants, options, participations or other
equivalents of or interests in (however designated) stock issued by that
corporation.

               "Certificated Securities" means Securities that are in the form
of the Securities attached hereto as Exhibit A-2.

<PAGE>   8

               "Common Stock" shall mean the shares of Common Stock, $0.01 par
value, of the Company as it exists on the date of this Indenture or any other
shares of Capital Stock of the Company into which the Common Stock shall be
reclassified or changed.

               "Company" means the party named as the "Company" in the first
paragraph of this Indenture until a successor replaces it pursuant to the
applicable provisions of this Indenture and, thereafter, shall mean such
successor. The foregoing sentence shall likewise apply to any subsequent such
successor or successors.

               "Company Request" or "Company Order" means a written request or
order signed in the name of the Company by its Chairman of the Board, its
President, a Corporate Vice President, a Senior Vice President or a Vice
President, and by its Treasurer, an Assistant Treasurer, its Secretary or an
Assistant Secretary, and delivered to the Trustee.

               "Debt" means with respect to the Company at any date, without
duplication, obligations (other than nonrecourse obligations) for borrowed money
or evidenced by bonds, debentures, notes or similar instruments.

               "Default" means any event which is, or after notice or passage of
time or both would be, an Event of Default.

               "Global Securities" means Securities that are in the form of the
Securities attached hereto as Exhibit A-1, and to the extent that such
Securities are required to bear the Legend required by Section 2.06, such
Securities will be in the form of a 144A Global Security.

               "Holder" or "Securityholder" means a person in whose name a
Security is registered on the Registrar's books.

               "Indenture" means this Indenture, as amended or supplemented from
time to time in accordance with the terms hereof, including the provisions of
the TIA that are deemed to be a part hereof.

               "Institutional Accredited Investor Security" means a Security in
the form of the Security attached hereto as Exhibit A-2, representing Securities
sold to institutional "accredited investors" (as defined in Rule 501(a)(1), (2),
(3) and (7) under the Securities Act).

               "Issue Date" of any Security means the date on which the Security
was originally issued or deemed issued as set forth on the face of the Security.

               "Issue Price" of any Security means, in connection with the
original issuance of such Security, the initial issue price at which the
Security is sold as set forth on the face of the Security.

               "Officer" means the Chairman of the Board, the President, any
Corporate Vice President, any Senior Vice President, any Vice President, the
Treasurer or the Secretary or any Assistant Treasurer or Assistant Secretary of
the Company.

                                       2
<PAGE>   9

               "Officers' Certificate" means a written certificate containing
the information specified in Sections 13.04 and 13.05, signed in the name of the
Company by its Chairman of the Board, its President, a Corporate Vice President,
a Senior Vice President or a Vice President, and by its Treasurer, an Assistant
Treasurer, its Secretary or an Assistant Secretary, and delivered to the
Trustee. An Officers' Certificate given pursuant to Section 4.03 shall be signed
by the principal executive, financial or accounting officer of the Company but
need not contain the information specified in Sections 13.04 and 13.05.

               "Opinion of Counsel" means a written opinion containing the
information specified in Sections 13.04 and 13.05, from legal counsel who is
acceptable to the Trustee. The counsel may be an employee of, or counsel to, the
Company or the Trustee.

               "Original Issue Discount" of any Security means the difference
between the Issue Price and the Principal Amount at Maturity of the Security as
set forth on the face of the Security.

               "person" means any individual, corporation, limited liability
company, partnership, joint venture, association, joint-stock company, trust,
unincorporated organization, or government or any agency or political
subdivision thereof.

               "Principal Amount at Maturity" of a Security means the Principal
Amount at Maturity as set forth on the face of the Security.

               "Redemption Date" or "redemption date" shall mean the date
specified for redemption of the Securities in accordance with the terms of the
Securities and this Indenture.

               "Redemption Price" or "redemption price" shall have the meaning
set forth in paragraph 5 of the Securities.

               "Responsible Officer", when used with respect to the Trustee,
means any officer within the Corporate Trust Department (or any successor group)
including without limitation any vice president, any assistant vice president,
any assistant secretary or any other officer of the Trustee customarily
performing functions similar to those performed by any of the above-designated
officers and also means, with respect to a particular corporate trust matter,
any other officer to whom such matter is referred because of his knowledge of
and familiarity with the particular subject.

               "Restricted Security" means a Security required to bear the
restrictive legend set forth in the form of Security set forth in Exhibits A-1
and A-2 of this Indenture.

               "Rule 144A" means Rule 144A under the Securities Act (or any
successor provision), as it may be amended from time to time.

               "SEC" means the Securities and Exchange Commission.

               "Securities" means any of the Company's Liquid Yield Option Notes
due 2020 (Zero Coupon-Subordinated), as amended or supplemented from time to
time, issued under this Indenture.

                                       3
<PAGE>   10

               "Securityholder" or "Holder" means a person in whose name a
Security is registered on the Registrar's books.

               "Senior Indebtedness" means the principal, premium (if any) and
unpaid interest on all present and future (i) indebtedness of the Company for
borrowed money, (ii) obligations of the Company evidenced by bonds, debentures,
notes or similar instruments, (iii) all obligations of the Company under (a)
interest rate swaps, caps, collars, options, and similar arrangements, (b) any
foreign exchange contract, currency swap contract, futures contract, currency
option contract, or other foreign currency hedge, and (c) credit swaps, caps,
floors, collars and similar arrangements, (iv) indebtedness incurred, assumed or
guaranteed by the Company in connection with the acquisition by it or a
subsidiary of the Company of any business, properties or assets (except
purchase-money indebtedness classified as accounts payable under generally
accepted accounting principles), (v) all obligations and liabilities (contingent
or otherwise) in respect of leases of the Company required, in conformity with
generally accepted accounting principles, to be accounted for as capitalized
lease obligations on the balance sheet of the Company and all obligations and
liabilities (contingent or otherwise) under any lease or related document
(including a purchase agreement) in connection with the lease or real property
which provides that the Company is contractually obligated to purchase or cause
a third party to purchase the leased property and thereby guarantee a minimum
residual value of the leased property to the lessor and the obligations of the
Company under such lease or related document to purchase or to cause a third
party to purchase such leased property, (vi) reimbursement obligations of the
Company in respect of letters of credit relating to indebtedness or other
obligations of the Company that qualify as indebtedness or obligations of the
kind referred to in clauses (i) through (v) above, and (vii) obligations of the
Company under direct or indirect guaranties in respect of, and obligations
(contingent or otherwise) to purchase or otherwise acquire, or otherwise to
assure a creditor against loss in respect of, indebtedness or obligations of
others of the kinds referred to in clauses (i) through (vi) above, in each case
unless in the instrument creating or evidencing the indebtedness or obligation
or pursuant to which the same is outstanding it is provided (i) that such
indebtedness or obligation is not senior in right of payment to the Securities
or (ii) that such indebtedness or obligation is subordinated to any other
indebtedness or obligation of the Company, unless such indebtedness or
obligation expressly provides that such indebtedness or obligations be senior in
right of payment to the Securities.

               "Special Record Date" means for the payment of any Defaulted
Interest, the date fixed by the Trustee pursuant to Section 10.02(b).

               "Stated Maturity", when used with respect to any Security, means
the date specified in such Security as the fixed date on which an amount equal
to the Principal Amount at Maturity of such Security is due and payable.

               "Subsidiary" means (i) a corporation, a majority of whose Capital
Stock with voting power, under ordinary circumstances, to elect directors is, at
the date of determination, directly or indirectly owned by the Company, by one
or more subsidiaries of the Company or by the Company and one or more
Subsidiaries of the Company, (ii) a partnership in which the Company or a
Subsidiary of the Company holds a majority interest in the equity capital or
profits of such partnership, or (iii) any other person (other than a
corporation) in which the Company, a Subsidiary of the Company or the Company
and one or more Subsidiaries of the Company,

                                       4
<PAGE>   11

directly or indirectly, at the date of determination, has (x) at least a
majority ownership interest or (y) the power to elect or direct the election of
a majority of the directors or other governing body of such person.

               "Tax Event" means that the Company shall have received an opinion
from independent tax counsel experienced in such matters to the effect that, on
or after November 1, 2000, as a result of (a) any amendment to, or change
(including any announced prospective change) in, the laws (or any regulations
thereunder) of the United States or any political subdivision or taxing
authority thereof or therein or (b) any amendment to, or change in, an
interpretation or application of such laws or regulations by any legislative
body, court, governmental agency or regulatory authority, in each case which
amendment or change is enacted, promulgated, issued or announced or which
interpretation is issued or announced or which action is taken, on or after
November 1, 2000, there is more than an insubstantial risk that interest
(including Original Issue Discount) payable on the Securities either (i) would
not be deductible on a current accrual basis or (ii) would not be deductible
under any other method, in either case in whole or in part, by the Company (by
reason of deferral, disallowance, or otherwise) for United States Federal income
tax purposes.

               "TIA" means the Trust Indenture Act of 1939 as in effect on the
date of this Indenture, provided, however, that in the event the TIA is amended
after such date, TIA means, to the extent required by any such amendment, the
TIA as so amended.

               "trading day" means a day during which trading in securities
generally occurs on the New York Stock Exchange or, if the Common Stock is not
listed on the New York Stock Exchange, on the principal other national or
regional securities exchange on which the Common Stock is then listed or, if the
Common Stock is not listed on a national or regional securities exchange, on the
National Association of Securities Dealers Automated Quotation System or, if the
Common Stock is not quoted on the National Association of Securities Dealers
Automated Quotation System, on the principal other market on which the Common
Stock is then traded.

               "Trustee" means the party named as the "Trustee" in the first
paragraph of this Indenture until a successor replaces it pursuant to the
applicable provisions of this Indenture and, thereafter, shall mean such
successor. The foregoing sentence shall likewise apply to any subsequent such
successor or successors.

               SECTION 1.02  Other Definitions.

<TABLE>
<CAPTION>

                                                                 Defined in
Term    Section
----    -------

<S>                                                             <C>
"Agent Members"..................................................2.12(e)
"Associate"......................................................3.09(a)
"Average Quoted Price".............................................11.01
"Bankruptcy Law"....................................................6.01
"beneficial owner"...............................................3.09(a)
"cash"...........................................................3.08(b)
"Change in Control"..............................................3.09(a)
</TABLE>

                                       5
<PAGE>   12
<TABLE>
<CAPTION>

<S>                                                             <C>
"Change in Control Purchase Date"................................3.09(a)
"Change in Control Purchase Notice"..............................3.09(c)
"Change in Control Purchase Price"...............................3.09(a)
"Company Notice".................................................3.08(e)
"Company Notice Date"............................................3.08(c)
"Conversion Agent"..................................................2.03
"Conversion Date"..................................................11.02
"Conversion Rate"..................................................11.01
"Custodian".........................................................6.01
"Defaulted Interest"............................................10.02(b)
"Depositary".....................................................2.01(a)
"Event of Default"..................................................6.01
"Exchange Act"...................................................3.08(d)
"Ex-Dividend Time".................................................11.01
"Extraordinary Cash Dividend"......................................11.08
"Institutional Accredited Investors".............................2.01(b)
"Interest Payment Date"............................................10.01
"Legal Holiday"....................................................13.08
"Legend".........................................................2.06(f)
"Market Price"...................................................3.08(d)
"Notice of Default".................................................6.01
"Paying Agent"......................................................2.03
"Purchase Date"..................................................3.08(a)
"Purchase Notice"................................................3.08(a)
"Purchase Price".................................................3.08(a)
"QIB"............................................................2.01(a)
"Quoted Price".....................................................11.01
"Registrar".........................................................2.03
"Regular Record Date"..............................................10.01
"Restated Principal Amount"........................................10.01
"Rights"...........................................................11.19
"Rights Agreement".................................................11.19
"Rule 144A Information".............................................4.06
"Sale Price".....................................................3.08(d)
"Securities Act".................................................3.08(d)
"Tax Event Date"...................................................10.01
"Time of Determination"............................................11.01
</TABLE>

               SECTION 1.03..Incorporation by Reference of Trust Indenture Act.
Whenever this Indenture refers to a provision of the TIA, the provision is
incorporated by reference in and made a part of this Indenture. The following
TIA terms used in this Indenture have the following meanings:

               "Commission" means the SEC.

               "indenture securities" means the Securities.

                                       6
<PAGE>   13

               "indenture security holder" means a Securityholder.

               "indenture to be qualified" means this Indenture.

               "indenture trustee" or "institutional trustee" means the Trustee.

               "obligor" on the indenture securities means the Company.

               All other TIA terms used in this Indenture that are defined by
the TIA, defined by TIA reference to another statute or defined by SEC rule have
the meanings assigned to them by such definitions.

               SECTION 1.04 Rules of Construction.  Unless the context otherwise
requires:

               (1)    a term has the meaning assigned to it;

               (2)    an accounting term not otherwise defined has the meaning
assigned to it in accordance with generally accepted accounting principles as in
effect from time to time;

               (3)    "or" is not exclusive;

               (4)    "including" means including, without limitation; and

               (5)    words in the singular include the plural, and words in the
plural include the singular.

                                    ARTICLE 2
\
                                 THE SECURITIES

              SECTION 2.01  Form and Dating. The Securities and the Trustee's
certificate of authentication shall be substantially in the form of Exhibits A-1
and A-2, which are a part of this Indenture. The Securities may have notations,
legends or endorsements required by law, stock exchange rule or usage (provided
that any such notation, legend or endorsement required by usage is in a form
acceptable to the Company). The Company shall provide any such notations,
legends or endorsements to the Trustee in writing. Each Security shall be dated
the date of its authentication.

             (a) 144A Global Securities. Securities offered and sold within
        the United States to qualified institutional investors as defined in
        Rule 144A ("QIBs") in reliance on Rule 144A shall be issued, initially
        in the form of a 144A Global Security, which shall be deposited with the
        Trustee at its corporate trust offices, as custodian for the Depositary
        and registered in the name of The Depository Trust Company ("DTC") or
        the nominee thereof (such depositary, or any successor thereto, and any
        such nominee being hereinafter referred to as the "Depositary"), duly
        executed by the Company and authenticated by the Trustee as hereinafter
        provided. The aggregate principal amount of the 144A Global Securities
        may from time to time be increased or decreased by

                                       7
<PAGE>   14

        adjustments made on the records of the Trustee and the Depositary as
        hereinafter provided.

               (b) Institutional Accredited Investor Securities. Except as
        provided in this Section 2.01, 2.06 or 2.12, owners of beneficial
        interests in Global Securities will not be entitled to receive physical
        delivery of Certificated Securities. Securities offered and sold within
        the United States to institutional accredited investors as defined in
        Rule 501(a)(1), (2) (3) and (7) under the Securities Act ("Institutional
        Accredited Investors") shall be issued, initially in the form of an
        Institutional Accredited Investor Security, duly executed by the Company
        and authenticated by the Trustee as hereinafter provided.

               (c) Global Securities in General. Each Global Security shall
        represent such of the outstanding Securities as shall be specified
        therein and each shall provide that it shall represent the aggregate
        amount of outstanding Securities from time to time endorsed thereon and
        that the aggregate amount of outstanding Securities represented thereby
        may from time to time be reduced or increased, as appropriate, to
        reflect exchanges, redemptions and conversions.

               Any adjustment of the aggregate principal amount of a Global
Security to reflect the amount of any increase or decrease in the amount of
outstanding Securities represented thereby shall be made by the Trustee in
accordance with instructions given by the Holder thereof as required by Section
2.12 hereof and shall be made on the records of the Trustee and the Depositary.

               (d) Book-Entry Provisions. This Section 2.01(d) shall apply only
        to Global Securities deposited with or on behalf of the Depositary.

               The Company shall execute and the Trustee shall, in accordance
with this Section 2.01(d), authenticate and the Registrar shall deliver
initially one or more Global Securities that (a) shall be registered in the name
of the Depositary, (b) shall be delivered by the Registrar to the Depositary or
pursuant to the Depositary's instructions and (c) shall bear legends
substantially to the following effect:

        "UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
        THE DEPOSITORY TRUST COMPANY TO THE ISSUER OR ITS AGENT FOR REGISTRATION
        OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS
        REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
        REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST
        COMPANY (AND ANY PAYMENT HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER
        ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY
        TRUST COMPANY), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
        OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER
        HEREOF, CEDE & CO., HAS AN INTEREST HEREIN. TRANSFERS OF THIS GLOBAL
        SECURITY SHALL BE LIMITED TO TRANSFERS, IN WHOLE BUT NOT IN PART, TO
        NOMINEES OF THE

                                       8
<PAGE>   15

        DEPOSITORY TRUST COMPANY OR TO A SUCCESSOR THEREOF OR SUCH SUCCESSOR'S
        NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY SHALL BE
        LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH
        IN ARTICLE TWO OF THE INDENTURE REFERRED TO ON THE REVERSE HEREOF."

               (e) Certificated Securities. Securities not issued as interests
        in the Global Securities will be issued in certificated form
        substantially in the form of Exhibit A-2 attached hereto.

               SECTION 2.02  Execution and Authentication. The Securities shall
be executed on behalf of the Company by its Chairman of the Board, its
President, one of its Corporate Vice Presidents, one of its Senior Vice
Presidents or one of its Vice Presidents, under its corporate seal reproduced
thereon, and attested by its Secretary or one of its Assistant Secretaries. The
signature of any of these officers on the Securities may be manual or facsimile.

               Securities bearing the manual or facsimile signatures of
individuals who were at the time of the execution of the Securities the proper
Officers of the Company shall bind the Company, notwithstanding that such
individuals or any of them have ceased to hold such offices prior to the
authentication and delivery of such Securities or did not hold such offices at
the date of authentication of such Securities.

               No Security shall be entitled to any benefit under this Indenture
or be valid or obligatory for any purpose unless there appears on such Security
a certificate of authentication substantially in the form provided for herein
duly executed by the Trustee by manual signature of an authorized signatory, and
such certificate upon any Security shall be conclusive evidence, and the only
evidence, that such Security has been duly authenticated and delivered
hereunder.

               The Trustee shall authenticate and the Registrar shall deliver
Securities for original issue in an aggregate Principal Amount at Maturity of up
to and including $657,451,000 upon a Company Order without any further action by
the Company. The aggregate Principal Amount at Maturity of Securities
outstanding at any time may not exceed the amount set forth in the foregoing
sentence, except as provided in Section 2.07.

               The Securities shall be issued only in registered form without
coupons and only in denominations of $1,000 of Principal Amount at Maturity and
any integral multiple thereof.

               SECTION 2.03 Registrar, Paying Agent and Conversion Agent. The
Company shall maintain an office or agency where Securities may be presented for
registration of transfer or for exchange ("Registrar"), an office or agency
where Securities may be presented for purchase or payment ("Paying Agent") and
an office or agency where Securities may be presented for conversion
("Conversion Agent"). The Registrar shall keep a register of the Securities and
of their transfer and exchange. The Company may have one or more co-registrars,
one or more additional paying agents and one or more additional conversion
agents. The term Paying Agent includes any additional paying agent, including
any named pursuant to Section 4.05. The term Conversion Agent includes any
additional conversion agent, including any named pursuant to Section 4.05.

                                       9
<PAGE>   16

               The Company shall enter into an appropriate agency agreement with
any Registrar, Paying Agent, Conversion Agent or co-registrar (other than the
Trustee). The agreement shall implement the provisions of this Indenture that
relate to such agent. The Company shall notify the Trustee of the name and
address of any such agent. If the Company fails to maintain a Registrar, Paying
Agent or Conversion Agent, the Trustee shall act as such and shall be entitled
to appropriate compensation therefor pursuant to Section 7.07. The Company or
any Subsidiary or an Affiliate of either of them may act as Paying Agent,
Registrar, Conversion Agent or co-registrar.

               The Company initially appoints the Trustee as Registrar,
Conversion Agent and Paying Agent in connection with the Securities.

               SECTION 2.04 Paying Agent to Hold Money and Securities in Trust.
Except as otherwise provided herein, on or prior to 11:30 a.m. New York time on
each due date of payments in respect of any Security, the Company shall deposit
with the Paying Agent a sum of money (in immediately available funds if
deposited on the due date) or Common Stock sufficient to make such payments when
so becoming due. The Company shall require each Paying Agent (other than the
Trustee) to agree in writing that the Paying Agent shall hold in trust for the
benefit of Securityholders or the Trustee all money and Common Stock held by the
Paying Agent for the making of payments in respect of the Securities and shall
notify the Trustee of any default by the Company in making any such payment. At
any time during the continuance of any such default, the Paying Agent shall,
upon the written request of the Trustee, forthwith pay to the Trustee all money
and deliver to the Trustee all Common Stock so held in trust. If the Company, a
Subsidiary or an Affiliate of either of them acts as Paying Agent, it shall
segregate the money and Common Stock held by it as Paying Agent and hold it as a
separate trust fund. The Company at any time may require a Paying Agent to pay
all money and deliver all Common Stock held by it to the Trustee and to account
for any funds and Common Stock disbursed by it. Upon doing so, the Paying Agent
shall have no further liability for the money or Common Stock.

               SECTION 2.05 Securityholder Lists. The Trustee shall preserve in
as current a form as is reasonably practicable the most recent list available to
it of the names and addresses of Securityholders. If the Trustee is not the
Registrar, the Company shall cause to be furnished to the Trustee at least
semiannually on May 1 and November 1 a listing of Securityholders dated within
15 days of the date on which the list is furnished and at such other times as
the Trustee may request in writing a list in such form and as of such date as
the Trustee may reasonably require of the names and addresses of
Securityholders.

               SECTION 2.06 Transfer and Exchange. Subject to Section 2.12
hereof, (a) upon surrender for registration of transfer of any Security,
together with a written instrument of transfer satisfactory to the Registrar
duly executed by the Securityholder or such Securityholder's attorney duly
authorized in writing, at the office or agency of the Company designated as
Registrar or co-registrar pursuant to Section 2.03, the Company shall execute,
and the Trustee shall authenticate and the Registrar shall deliver, in the name
of the designated transferee or transferees, one or more new Securities of any
authorized denomination or denominations, of a like aggregate Principal Amount
at Maturity. The Company shall not charge a service charge for any registration
of transfer or exchange, but the Company may require payment of a sum sufficient
to pay all taxes, assessments or other governmental charges that may

                                       10
<PAGE>   17

be imposed in connection with the transfer or exchange of the Securities from
the Securityholder requesting such transfer or exchange.

               At the option of the Holder, Securities may be exchanged for
other Securities of any authorized denomination or denominations, of a like
aggregate Principal Amount at Maturity, upon surrender of the Securities to be
exchanged, together with a written instrument of transfer satisfactory to the
Registrar duly executed by the Securityholder or such Securityholder's attorney
duly authorized in writing, at such office or agency. Whenever any Securities
are so surrendered for exchange, the Company shall execute, and the Trustee
shall authenticate and the Registrar shall deliver, the Securities which the
Holder making the exchange is entitled to receive.

               The Company shall not be required to make, and the Registrar need
not register, transfers or exchanges of Securities selected for redemption
(except, in the case of Securities to be redeemed in part, the portion thereof
not to be redeemed) or any Securities in respect of which a Purchase Notice or
Change in Control Purchase Notice has been given and not withdrawn by the Holder
thereof in accordance with the terms of this Indenture (except, in the case of
Securities to be purchased in part, the portion thereof not to be purchased) or
any Securities for a period of 15 days before a selection of Securities to be
redeemed.

               (b) Notwithstanding any provision to the contrary herein, so long
as a Global Security remains outstanding and is held by or on behalf of the
Depositary, transfers of a Global Security, in whole or in part, shall be made
only in accordance with Section 2.12 and this Section 2.06(b). Transfers of a
Global Security shall be limited to transfers of such Global Security in whole,
or in part, to nominees of the Depositary or to a successor of the Depositary or
such successor's nominee.

               (c) Successive registrations and registrations of transfers and
exchanges as aforesaid may be made from time to time as desired, and each such
registration shall be noted on the register for the Securities.

               (d) Any Registrar appointed pursuant to Section 2.03 hereof shall
provide to the Trustee such information as the Trustee may reasonably require in
connection with the delivery by such Registrar of Securities upon transfer or
exchange of Securities.

               (e) No Registrar shall be required to make registrations of
transfer or exchange of Securities during any periods designated in the text of
the Securities or in this Indenture as periods during which such registration of
transfers and exchanges need not be made.

               (f) If Securities are issued upon the transfer, exchange or
replacement of Securities subject to restrictions on transfer and bearing the
legends set forth on the form of Security attached hereto as Exhibits A-1 and
A-2 setting forth such restrictions (collectively, the "Legend"), or if a
request is made to remove the Legend on a Security, the Securities so issued
shall bear the Legend, or the Legend shall not be removed, as the case may be,
unless (i) there is delivered to the Company and the Registrar such satisfactory
evidence, which shall include an Opinion of Counsel, as may be reasonably
required by the Company and the Registrar, that neither the Legend nor the
restrictions on transfer set forth therein are required to ensure that

                                       11
<PAGE>   18

transfers thereof comply with the provisions of Rule 144A or Rule 144 under the
Securities Act or that such Securities are not "restricted" within the meaning
of Rule 144 under the Securities Act. Upon (i) provision of such satisfactory
evidence, or (ii) notification by the Company to the Trustee and Registrar of
the sale of such Security pursuant to a registration statement that is effective
at the time of such sale, the Trustee, at the written direction of the Company,
shall authenticate and the Registrar shall deliver a Security that does not bear
the Legend. If the Legend is removed from the face of a Security and the
Security is subsequently held by an Affiliate of the Company, the Legend shall
be reinstated.

               SECTION 2.07  Replacement Securities. If (a) any mutilated
Security is surrendered to the Trustee, or (b) the Company and the Trustee
receive evidence to their satisfaction of the destruction, loss or theft of any
Security, and there is delivered to the Company and the Trustee such security or
indemnity as may be required by them to save each of them harmless, then, in the
absence of notice to the Company or the Trustee that such Security has been
acquired by a bona fide purchaser, the Company shall execute and upon its
written request the Trustee shall authenticate and the Registrar shall deliver,
in exchange for any such mutilated Security or in lieu of any such destroyed,
lost or stolen Security, a new Security of like tenor and Principal Amount at
Maturity, bearing a number not contemporaneously outstanding.

               In case any such mutilated, destroyed, lost or stolen Security
has become or is about to become due and payable, or is about to be purchased by
the Company pursuant to Article 3 hereof, the Company in its discretion may,
instead of issuing a new Security, pay or purchase such Security, as the case
may be.

               Upon the issuance of any new Securities under this Section, the
Company may require the payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto and any other
expenses (including the fees and expenses of the Trustee) connected therewith.

               Every new Security issued pursuant to this Section in lieu of any
mutilated, destroyed, lost or stolen Security shall constitute an original
additional contractual obligation of the Company, whether or not the destroyed,
lost or stolen Security shall be at any time enforceable by anyone, and shall be
entitled to all benefits of this Indenture equally and proportionately with any
and all other Securities duly issued hereunder.

               The provisions of this Section are exclusive and shall preclude
(to the extent lawful) all other rights and remedies with respect to the
replacement or payment of mutilated, destroyed, lost or stolen Securities.

               SECTION 2.08 Outstanding Securities; Determinations of Holders'
Action. Securities outstanding at any time are all the Securities authenticated
by the Trustee except for those cancelled by it, those delivered to it for
cancellation and those described in this Section 2.08 as not outstanding. A
Security does not cease to be outstanding because the Company or an Affiliate
thereof holds the Security; provided, however, that in determining whether the
Holders of the requisite Principal Amount at Maturity of Securities have given
or concurred in any request, demand, authorization, direction, notice, consent
or waiver hereunder, Securities owned by the Company or any other obligor upon
the Securities or any Affiliate of the Company or

                                       12
<PAGE>   19

such other obligor shall be disregarded and deemed not to be outstanding, except
that, in determining whether the Trustee shall be protected in relying upon any
such request, demand, authorization, direction, notice, consent or waiver, only
Securities which the Trustee knows to be so owned shall be so disregarded.
Subject to the foregoing, only Securities outstanding at the time of such
determination shall be considered in any such determination (including, without
limitation, determinations pursuant to Articles 6 and 9).

               If a Security is replaced pursuant to Section 2.07, it ceases to
be outstanding unless the Trustee receives proof satisfactory to it that the
replaced Security is held by a bona fide purchaser.

               If the Paying Agent holds, in accordance with this Indenture, on
a Redemption Date, or on the Business Day following the Purchase Date or a
Change in Control Purchase Date, or on Stated Maturity, money or securities, if
permitted hereunder, sufficient to pay Securities payable on that date, then
immediately after such Redemption Date, Purchase Date, Change in Control
Purchase Date or Stated Maturity, as the case may be, such Securities shall
cease to be outstanding and Original Issue Discount and interest, if any, on
such Securities shall cease to accrue; provided, that if such Securities are to
be redeemed, notice of such redemption has been duly given pursuant to this
Indenture or provision therefor satisfactory to the Trustee has been made.

               If a Security is converted in accordance with Article 11, then
from and after the time of conversion on the Conversion Date, such Security
shall cease to be outstanding and Original Issue Discount and interest, if any,
shall cease to accrue on such Security.

               SECTION 2.09 Temporary Securities. Pending the preparation of
definitive Securities, the Company may execute, and upon Company Order the
Trustee shall authenticate and the Registrar shall deliver, temporary Securities
which are printed, lithographed, typewritten, mimeographed or otherwise
produced, in any authorized denomination, substantially of the tenor of the
definitive Securities in lieu of which they are issued and with such appropriate
insertions, omissions, substitutions and other variations as the officers
executing such Securities may determine, as conclusively evidenced by their
execution of such Securities.

               If temporary Securities are issued, the Company will cause
definitive Securities to be prepared without unreasonable delay. After the
preparation of definitive Securities, the temporary Securities shall be
exchangeable for definitive Securities upon surrender of the temporary
Securities at the office or agency of the Company designated for such purpose
pursuant to Section 2.03, without charge to the Holder. Upon surrender for
cancellation of any one or more temporary Securities the Company shall execute
and the Trustee shall authenticate and the Registrar shall deliver in exchange
therefor a like Principal Amount at Maturity of definitive Securities of
authorized denominations. Until so exchanged the temporary Securities shall in
all respects be entitled to the same benefits under this Indenture as definitive
Securities.

               SECTION 2.10 Cancellation. All Securities surrendered for
payment, purchase by the Company pursuant to Article 3, conversion, redemption
or registration of transfer or exchange shall, if surrendered to any person
other than the Trustee, be delivered to the Trustee and shall be promptly
cancelled by it. The Company may at any time deliver to the

                                       13
<PAGE>   20
Trustee for cancellation any Securities previously authenticated and delivered
hereunder which the Company may have acquired in any manner whatsoever, and all
Securities so delivered shall be promptly cancelled by the Trustee. The Company
may not issue new Securities to replace Securities it has paid or delivered to
the Trustee for cancellation or that any Holder has converted pursuant to
Article 11. No Securities shall be authenticated in lieu of or in exchange for
any Securities cancelled as provided in this Section, except as expressly
permitted by this Indenture. Subject to the Trustee's record retention
requirements in accordance with the Exchange Act, all cancelled Securities held
by the Trustee shall be destroyed by the Trustee and the Trustee shall deliver a
certificate of destruction to the Company.

               SECTION 2.11 Persons Deemed Owners. Prior to due presentment of a
Security for registration of transfer, the Company, the Trustee and any agent of
the Company or the Trustee may treat the person in whose name such Security is
registered as the owner of such Security for the purpose of receiving payment of
principal of the Security or the payment of any Redemption Price, Purchase Price
or Change in Control Purchase Price in respect thereof, and interest thereon,
for the purpose of conversion and for all other purposes whatsoever, whether or
not such Security be overdue, and neither the Company, the Trustee nor any agent
of the Company or the Trustee shall be affected by notice to the contrary.

               SECTION 2.12 Global Securities.

               (a) Notwithstanding any other provisions of this Indenture or the
Securities, (A) transfers of a Global Security, in whole or in part, shall be
made only in accordance with Section 2.06 and Section 2.12(a)(i), (B) transfer
of a beneficial interest in a Global Security for a Certificated Security shall
comply with Section 2.06 and Section 2.12(b)(ii) below, and (C) transfers of a
Certificated Security shall comply with Section 2.06 and Section 2.12(b)(iii)
and (iv) below.

               (i) Transfer of Global Security. A Global Security may not be
               transferred, in whole or in part, to any person other than the
               Depositary or a nominee or any successor thereof, and no such
               transfer to any such other person may be registered; provided
               that this clause (i) shall not prohibit any transfer of a
               Security that is issued in exchange for a Global Security but is
               not itself a Global Security. No transfer of a Security to any
               person shall be effective under this Indenture or the Securities
               unless and until such Security has been registered in the name of
               such person. Nothing in this Section 2.12(a)(i) shall prohibit or
               render ineffective any transfer of a beneficial interest in a
               Global Security effected in accordance with the other provisions
               of this Section 2.12(a).

               (ii) Restrictions on Transfer of a Beneficial Interest in a
               Global Security for a Certificated Security. A beneficial
               interest in a Global Security may not be exchanged for a
               Certificated Security except upon satisfaction of the
               requirements set forth below. Upon receipt by the Trustee of a
               transfer of a beneficial interest in a Global Security in
               accordance with Applicable Procedures for a Certificated Security
               in the form satisfactory to the Trustee, together with:

                                       14
<PAGE>   21

               (a)    so long as the Securities are Restricted Securities,
                      certification, in the form set forth in Exhibit B-1, and,
                      if requested by the Company or the Registrar,
                      certification in the form set forth in Exhibit B-2, that
                      such beneficial interest in the Global Security is being
                      transferred to an Institutional Accredited Investor in
                      accordance with Sections 501(a)(1), (2), (3) or (7) of the
                      Securities Act; and

               (b)    written instructions to the Trustee to make, or direct the
                      Registrar to make, an adjustment on its books and records
                      with respect to such Global Security to reflect a decrease
                      in the aggregate Principal Amount of the Securities
                      represented by the Global Security, such instructions to
                      contain information regarding the Depositary account to be
                      credited with such decrease,

        then the Trustee shall cause, or direct the Registrar to cause, in
        accordance with the standing instructions and procedures existing
        between the Depositary and the Registrar, the aggregate Principal Amount
        at Maturity of Securities represented by the Global Security to be
        decreased by the aggregate Principal Amount at Maturity of the
        Certificated Security to be issued, shall issue such Certificated
        Security and shall debit or cause to be debited to the account of the
        person specified in such instructions a beneficial interest in the
        Global Security equal to the Principal Amount at Maturity of the
        Certificated Security so issued.

               (iii)  Transfer and Exchange of Certificated Securities. When
               Certificated Securities are presented to the Registrar with a
               request:

                      (x)    to register the transfer of such Certificated
                      Securities; or

                      (y)    to exchange such Certificated Securities for an
                      equal Principal Amount at Maturity of Certificated
                      Securities of other authorized denominations,

        the Registrar shall register the transfer or make the exchange as
        requested if its reasonable requirements for such transaction are met;
        provided, however, that the Certificated Securities surrendered for
        transfer or exchange:

               (a) shall be duly endorsed or accompanied by a written instrument
               of transfer in form reasonably satisfactory to the Company and
               the Registrar, duly executed by the Holder thereof or his
               attorney duly authorized in writing; and

               (b) so long as such Securities are Restricted Securities, such
               Securities are being transferred or exchanged pursuant to an
               effective registration statement under the Securities Act or
               pursuant to clause (A), (B) or (C) below, and are accompanied by
               the following additional information and documents, as
               applicable:

                                       15
<PAGE>   22

                             (A) if such Certificated Securities are being
                      delivered to the Registrar by a Holder for registration in
                      the name of such Holder, without transfer, a certification
                      from such Holder to that effect; or

                             (B) if such Certificated Securities are being
                      transferred to the Company, a certification to that
                      effect; or

                             (C) if such Certificated Securities are being
                      transferred pursuant to an exemption from registration in
                      accordance with Rule 144, (i) a certification to that
                      effect (in the form set forth in Exhibit B-1) and (ii) if
                      the Company or Registrar so requests, an opinion of
                      counsel or other evidence reasonably satisfactory to them
                      as to the compliance with the restrictions set forth in
                      the Legend.

               (iv) Restrictions on Transfer of a Certificated Security for a
               Beneficial Interest in a Global Security. A Certificated Security
               may not be exchanged for a beneficial interest in a Global
               Security except upon satisfaction of the requirements set forth
               below.

        Upon receipt by the Trustee of a Certificated Security, duly endorsed or
        accompanied by appropriate instruments of transfer, in form satisfactory
        to the Trustee, together with:

                      (a) so long as the Securities are Restricted Securities,
                      certification, in the form set forth in Exhibit B-1,
                      that such Certificated Security is being transferred to
                      a Qualified Institutional Buyer in accordance with Rule
                      144A; and

                      (b) written instructions directing the Trustee to make, or
                      to direct the Registrar to make, an adjustment on its
                      books and records with respect to such Global Security to
                      reflect an increase in the aggregate Principal Amount at
                      Maturity of the Securities represented by the Global
                      Security, such instructions to contain information
                      regarding the Depositary account to be credited with such
                      increase,

        then the Trustee shall cancel such Certificated Security and cause, or
        direct the Registrar to cause, in accordance with the standing
        instructions and procedures existing between the Depositary and the
        Registrar, the aggregate Principal Amount at Maturity of Securities
        represented by the Global Security to be increased by the aggregate
        Principal Amount at Maturity of the Certificated Security to be
        exchanged, and shall credit or cause to be credited to the account of
        the person specified in such instructions a beneficial interest in the
        Global Security equal to the Principal Amount at Maturity of the
        Certificated Security so cancelled. If no Global Securities are then
        outstanding, the Company shall issue and the Trustee shall authenticate,
        upon written order of the Company in the form of an Officers'
        Certificate, a new Global Security in the appropriate Principal Amount
        at Maturity.

               (b) Subject to the succeeding paragraph, every Security shall be
subject to the restrictions on transfer provided in the Legend. Whenever any
Restricted Security is presented or

                                       16
<PAGE>   23

surrendered for registration of transfer or for exchange for a Security
registered in a name other than that of the Holder, such Security must be
accompanied by a certificate in substantially the form set forth in Exhibit B-1,
dated the date of such surrender and signed by the Holder of such Security, as
to compliance with such restrictions on transfer. The Registrar shall not be
required to accept for such registration of transfer or exchange any Security
not so accompanied by a properly completed certificate.

               (c) The restrictions imposed by the Legend upon the
transferability of any Security shall cease and terminate when such Security has
been sold pursuant to an effective registration statement under the Securities
Act or transferred in compliance with Rule 144 under the Securities Act (or any
successor provision thereto) or, if earlier, upon the expiration of the holding
period applicable to sales thereof under Rule 144(k) under the Securities Act
(or any successor provision). Any Security as to which such restrictions on
transfer shall have expired in accordance with their terms or shall have
terminated may, upon a surrender of such Security for exchange to the Registrar
in accordance with the provisions of this Section 2.12 (accompanied, in the
event that such restrictions on transfer have terminated by reason of a transfer
in compliance with Rule 144 or any successor provision, by an opinion of counsel
having substantial experience in practice under the Securities Act and otherwise
reasonably acceptable to the Company, addressed to the Company and in form
acceptable to the Company, to the effect that the transfer of such Security has
been made in compliance with Rule 144 or such successor provision), be exchanged
for a new Security, of like tenor and aggregate Principal Amount at Maturity,
which shall not bear the restrictive Legend. The Company shall inform the
Trustee of the effective date of any registration statement registering the
Securities under the Securities Act. The Trustee shall not be liable for any
action taken or omitted to be taken by it in good faith in accordance with the
aforementioned opinion of counsel or registration statement.

               (d) As used in the preceding two paragraphs of this Section 2.12,
the term "transfer" encompasses any sale, pledge, transfer, hypothecation or
other disposition of any Security.

               (e) The provisions of clauses (1), (2), (3) and (4) below shall
apply only to Global Securities:

                      (1) Notwithstanding any other provisions of this Indenture
                      or the Securities, except as provided in Section
                      2.12(a)(ii), a Global Security shall not be exchanged in
                      whole or in part for a Security registered in the name of
                      any person other than the Depositary or one or more
                      nominees thereof, provided that a Global Security may be
                      exchanged for Securities registered in the names of any
                      person designated by the Depositary in the event that (i)
                      the Depositary has notified the Company that it is
                      unwilling or unable to continue as Depositary for such
                      Global Security or such Depositary has ceased to be a
                      "clearing agency" registered under the Exchange Act, and a
                      successor Depositary is not appointed by the Company
                      within 90 days or (ii) an Event of Default has occurred
                      and is continuing with respect to the Securities. Any
                      Global Security exchanged pursuant to clause (i) above
                      shall be so exchanged in whole and not in part, and any
                      Global Security exchanged pursuant to clause (ii) above
                      may

                                       17
<PAGE>   24

                      be exchanged in whole or from time to time in part as
                      directed by the Depositary. Any Security issued in
                      exchange for a Global Security or any portion thereof
                      shall be a Global Security; provided that any such
                      Security so issued that is registered in the name of a
                      person other than the Depositary or a nominee thereof
                      shall not be a Global Security.

                      (2) Securities issued in exchange for a Global Security or
                      any portion thereof shall be issued in definitive, fully
                      registered form, without interest coupons, shall have an
                      aggregate Principal Amount at Maturity equal to that of
                      such Global Security or portion thereof to be so
                      exchanged, shall be registered in such names and be in
                      such authorized denominations as the Depositary shall
                      designate and shall bear the applicable legends provided
                      for herein. Any Global Security to be exchanged in whole
                      shall be surrendered by the Depositary to the Trustee, as
                      Registrar. With regard to any Global Security to be
                      exchanged in part, either such Global Security shall be so
                      surrendered for exchange or, if the Trustee is acting as
                      custodian for the Depositary or its nominee with respect
                      to such Global Security, the Principal Amount at Maturity
                      thereof shall be reduced, by an amount equal to the
                      portion thereof to be so exchanged, by means of an
                      appropriate adjustment made on the records of the Trustee
                      and Registrar. Upon any such surrender or adjustment, the
                      Trustee shall authenticate and the Registrar shall deliver
                      the Security issuable on such exchange to or upon the
                      order of the Depositary or an authorized representative
                      thereof.

                      (3) Subject to the provisions of clause (5) below, the
                      registered Holder may grant proxies and otherwise
                      authorize any person, including Agent Members and persons
                      that may hold interests through Agent Members, to take any
                      action which a holder is entitled to take under this
                      Indenture or the Securities.

                      (4) In the event of the occurrence of any of the events
                      specified in clause (1) above, the Company will promptly
                      make available to the Trustee a reasonable supply of
                      Certificated Securities in definitive, fully registered
                      form, without interest coupons.

                      (5) Neither any members of, or participants in, the
                      Depositary ("Agent Members") nor any other persons on
                      whose behalf Agent Members may act shall have any rights
                      under this Indenture with respect to any Global Security
                      registered in the name of the Depositary or any nominee
                      thereof, or under any such Global Security, and the
                      Depositary or such nominee, as the case may be, may be
                      treated by the Company, the Trustee and any agent of the
                      Company or the Trustee as the absolute owner and holder of
                      such Global Security for all purposes whatsoever.
                      Notwithstanding the foregoing, nothing herein shall
                      prevent the Company, the Trustee or any agent of the
                      Company or the Trustee from giving effect to any written
                      certification, proxy or other authorization furnished by
                      the Depositary or such nominee, as the case may be, or
                      impair, as between the Depositary,

                                       18
<PAGE>   25

                      its Agent Members and any other person on whose behalf
                      an Agent Member may act, the operation of customary
                      practices of such persons governing the exercise of the
                      rights of a holder of any Security.

               SECTION 2.13 CUSIP Numbers. The Company in issuing the
Securities may use "CUSIP" numbers (if then generally in use), and, if so, the
Trustee shall use "CUSIP" numbers in notices of redemption as a convenience to
Holders; provided that any such notice may state that no representation is made
as to the correctness of such numbers either as printed on the Securities or as
contained in any notice of a redemption and that reliance may be placed only on
the other identification numbers printed on the Securities, and any such
redemption shall not be affected by any defect in or omission of such numbers.
The Company will promptly notify the Trustee of any change in the CUSIP numbers.

                                    ARTICLE 3

                            REDEMPTION AND PURCHASES

               SECTION 3.01 Right to Redeem; Notices to Trustee. The Company, at
its option, may redeem the Securities in accordance with the provisions of
paragraphs 5 and 7 of the Securities. If the Company elects to redeem Securities
pursuant to paragraph 5 of the Securities, it shall notify the Trustee in
writing of the Redemption Date, the Principal Amount at Maturity of Securities
to be redeemed and the Redemption Price.

               The Company shall give the notice to the Trustee provided for in
this Section 3.01 by a Company Order, in the case of any redemption of less than
all of the Securities, at least 30 days before the Redemption Date and, in the
case of any redemption of all of the Securities, on or prior to the date of
notice of redemption (in each case, unless a shorter notice shall be
satisfactory to the Trustee).

               SECTION 3.02 Selection of Securities to Be Redeemed. If less than
all the Securities are to be redeemed, the Trustee shall select the Securities
to be redeemed pro rata or by lot or by any other method the Trustee considers
fair and appropriate (so long as such method is not prohibited by the rules of
any stock exchange on which the Securities are then listed). The Trustee shall
make the selection at least 15 days but not more than 60 days before the
Redemption Date from outstanding Securities not previously called for
redemption. The Trustee may select for redemption portions of the Principal
Amount at Maturity of Securities that have denominations larger than $1,000.

               Securities and portions of them the Trustee selects shall be in
Principal Amounts at Maturity of $1,000 or an integral multiple of $1,000.
Provisions of this Indenture that apply to Securities called for redemption also
apply to portions of Securities called for redemption. The Trustee shall notify
the Company promptly of the Securities or portions of Securities to be redeemed.

               If any Security selected for partial redemption is converted in
part before termination of the conversion right with respect to the portion of
the Security so selected, the converted portion of such Security shall be deemed
(so far as may be) to be the portion selected

                                       19
<PAGE>   26

for redemption. Securities which have been converted during a selection of
Securities to be redeemed may be treated by the Trustee as outstanding for the
purpose of such selection.

               SECTION 3.03 Notice of Redemption. At least 15 days but not more
than 60 days before a Redemption Date, the Company shall mail a notice of
redemption by first-class mail, postage prepaid, to each Holder of Securities to
be redeemed.

               The notice shall identify the Securities to be redeemed and shall
state:

               (1) the Redemption Date;

               (2) the Redemption Price;

               (3) the Conversion Rate;

               (4) the name and address of the Paying Agent and Conversion
               Agent;

               (5) that Securities called for redemption may be converted at any
               time before the close of business on the Redemption Date;

               (6) that Holders who want to convert Securities must satisfy the
               requirements set forth in paragraph 8 of the Securities;

               (7) that Securities called for redemption must be surrendered to
               the Paying Agent to collect the Redemption Price;

               (8) if fewer than all the outstanding Securities are to be
               redeemed, the certificate number and Principal Amounts at
               Maturity of the particular Securities to be redeemed;

               (9) that, unless the Company defaults in making payment of such
               Redemption Price, Original Issue Discount on Securities called
               for redemption, and interest, if any, will cease to accrue on and
               after the Redemption Date; and

               (10) the CUSIP number of the Securities.

               At the Company's request, the Trustee shall give the notice of
redemption in the Company's name and at the Company's expense, provided that the
Company makes such request at least three Business Days prior to such notice of
redemption.

               SECTION 3.04 Effect of Notice of Redemption. Once notice of
redemption is given, Securities called for redemption become due and payable on
the Redemption Date and at the Redemption Price stated in the notice except for
Securities which are converted in accordance with the terms of this Indenture.
Upon surrender to the Paying Agent, such Securities shall be paid at the
Redemption Price stated in the notice.

               SECTION 3.05 Deposit of Redemption Price. Prior to or by 11:30
a.m. New York time on the Redemption Date, the Company shall deposit with the
Paying Agent (or if

                                       20
<PAGE>   27

the Company or a Subsidiary or an Affiliate of either of them is the Paying
Agent, shall segregate and hold in trust) money sufficient to pay the Redemption
Price of all Securities to be redeemed on that date other than Securities or
portions of Securities called for redemption which on or prior thereto have been
delivered by the Company to the Trustee for cancellation or have been converted.
The Paying Agent shall as promptly as practicable return to the Company any
money not required for that purpose because of conversion of Securities pursuant
to Article 11. If such money is then held by the Company in trust and is not
required for such purpose it shall be discharged from such trust.

               SECTION 3.06 Securities Redeemed in Part. Upon surrender of a
Security that is redeemed in part, the Company shall execute and the Trustee
shall authenticate and the Registrar shall deliver to the Holder a new Security
in an authorized denomination equal in Principal Amount at Maturity to the
unredeemed portion of the Security surrendered.

               SECTION 3.07 Conversion Arrangement on Call for Redemption. In
connection with any redemption of Securities, the Company may arrange for the
purchase and conversion of any Securities called for redemption by an agreement
with one or more investment bankers or other purchasers to purchase such
Securities by paying to the Trustee in trust for the Securityholders, on or
before the close of business on the Redemption Date, an amount that, together
with any amounts deposited with the Trustee by the Company for the redemption of
such Securities, is not less than the Redemption Price, of such Securities.
Notwithstanding anything to the contrary contained in this Article 3, the
obligation of the Company to pay the Redemption Price of such Securities, shall
be deemed to be satisfied and discharged to the extent such amount is so paid by
such purchasers. If such an agreement is entered into, any Securities not duly
surrendered for conversion by the Holders thereof may, at the option of the
Company, be deemed, to the fullest extent permitted by law, acquired by such
purchasers from such Holders and (notwithstanding anything to the contrary
contained in Article 11) surrendered by such purchasers for conversion, all as
of immediately prior to the close of business on the Redemption Date, subject to
payment of the above amount as aforesaid. The Trustee shall hold and pay to the
Holders whose Securities are selected for redemption any such amount paid to it
for purchase and conversion in the same manner as it would moneys deposited with
it by the Company for the redemption of Securities. Without the Trustee's prior
written consent, no arrangement between the Company and such purchasers for the
purchase and conversion of any Securities shall increase or otherwise affect any
of the powers, duties, responsibilities or obligations of the Trustee as set
forth in this Indenture, and the Company agrees to indemnify the Trustee from,
and hold it harmless against, any loss, liability or expense arising out of or
in connection with any such arrangement for the purchase and conversion of any
Securities between the Company and such purchasers, including the costs and
expenses incurred by the Trustee in the defense of any claim or liability
arising out of or in connection with the exercise or performance of any of its
powers, duties, responsibilities or obligations under this Indenture.

               SECTION 3.08 Purchase of Securities at Option of the Holder.

               (a) General. Securities shall be purchased by the Company
pursuant to paragraph 6 of the Securities as of November 1, 2003 and November 1,
2010 (each, a "Purchase Date"), at the purchase price specified therein (each, a
"Purchase Price"), at the option of the Holder thereof, upon:

                                       21
<PAGE>   28

               (1) delivery to the Paying Agent, by the Holder of a written
               notice of purchase (a "Purchase Notice") at any time from the
               opening of business on the date that is 20 Business Days prior to
               a Purchase Date until the close of business on such Purchase Date
               stating:

                      (A) the certificate number of the Security which the
                      Holder will deliver to be purchased,

                      (B) the portion of the Principal Amount at Maturity of the
                      Security which the Holder will deliver to be purchased,
                      which portion must be $1,000 or an integral multiple
                      thereof,

                      (C) that such Security shall be purchased as of the
                      Purchase Date pursuant to the terms and conditions
                      specified in paragraph 6 of the Securities and in this
                      Indenture, and

                      (D) in the event the Company elects, pursuant to Section
                      3.08(b), to pay the Purchase Price to be paid as of such
                      Purchase Date, in whole or in part, in shares of Common
                      Stock but such portion of the Purchase Price shall
                      ultimately be payable to such Holder entirely in cash
                      because any of the conditions to payment of the Purchase
                      Price in Common Stock is not satisfied prior to the close
                      of business on such Purchase Date, as set forth in Section
                      3.08(d), whether such Holder elects (i) to withdraw such
                      Purchase Notice as to some or all of the Securities to
                      which such Purchase Notice relates (stating the Principal
                      Amount at Maturity and certificate numbers of the
                      Securities as to which such withdrawal shall relate), or
                      (ii) to receive cash in respect of the entire Purchase
                      Price for all Securities (or portions thereof) to which
                      such Purchase Notice relates; and

               (2) delivery of such Security to the Paying Agent prior to, on or
               after the Purchase Date (together with all necessary
               endorsements) at the offices of the Paying Agent, such delivery
               being a condition to receipt by the Holder of the Purchase Price
               therefor; provided, however, that such Purchase Price shall be so
               paid pursuant to this Section 3.08 only if the Security so
               delivered to the Paying Agent shall conform in all respects to
               the description thereof in the related Purchase Notice.

               If a Holder, in such Holder's Purchase Notice and in any written
notice of withdrawal delivered by such Holder pursuant to the terms of Section
3.10, fails to indicate such Holder's choice with respect to the election set
forth in clause (D) of Section 3.08(a)(1), such Holder shall be deemed to have
elected to receive cash in respect of the Purchase Price for all Securities
subject to such Purchase Notice in the circumstances set forth in such clause
(D).

               The Company shall purchase from the Holder thereof, pursuant to
this Section 3.08, a portion of a Security if the Principal Amount at Maturity
of such portion is $1,000 or an integral multiple of $1,000. Provisions of this
Indenture that apply to the purchase of all of a Security also apply to the
purchase of such portion of such Security.

                                       22
<PAGE>   29

               Any purchase by the Company contemplated pursuant to the
provisions of this Section 3.08 shall be consummated by the delivery of the
consideration to be received by the Holder promptly following the later of the
Purchase Date and the time of delivery of the Security.

               Notwithstanding anything herein to the contrary, any Holder
delivering to the Paying Agent the Purchase Notice contemplated by this Section
3.08(a) shall have the right to withdraw such Purchase Notice at any time prior
to the close of business on the Purchase Date by delivery of a written notice of
withdrawal to the Paying Agent in accordance with Section 3.10.

               The Paying Agent shall promptly notify the Company of the receipt
by it of any Purchase Notice or written notice of withdrawal thereof.

               (b) Company's Right to Elect Manner of Payment of Purchase Price.
The Securities to be purchased pursuant to Section 3.08(a) may be paid for, at
the election of the Company, in U.S. legal tender ("cash") or Common Stock, or
in any combination of cash and Common Stock, subject to the conditions set forth
in Sections 3.08(c) and (d). The Company shall designate, in the Company Notice
delivered pursuant to Section 3.08(e), whether the Company will purchase the
Securities for cash or Common Stock, or, if a combination thereof, the
percentages of the Purchase Price of Securities in respect of which it will pay
in cash or Common Stock; provided that the Company will pay cash for fractional
interests in Common Stock. For purposes of determining the existence of
potential fractional interests, all Securities subject to purchase by the
Company held by a Holder shall be considered together (no matter how many
separate certificates are to be presented). Each Holder whose Securities are
purchased pursuant to this Section 3.08 shall receive the same percentage of
cash or Common Stock in payment of the Purchase Price for such Securities,
except (i) as provided in Section 3.08(d) with regard to the payment of cash in
lieu of fractional shares of Common Stock and (ii) in the event that the Company
is unable to purchase the Securities of a Holder or Holders for Common Stock
because any necessary qualifications or registrations of the Common Stock under
applicable state securities laws cannot be obtained, the Company may purchase
the Securities of such Holder or Holders for cash. The Company may not change
its election with respect to the consideration (or components or percentages of
components thereof) to be paid once the Company has given its Company Notice to
Securityholders except pursuant to this Section 3.08(b) or pursuant to Section
3.08(d) in the event of a failure to satisfy, prior to the close of business on
the Purchase Date, any condition to the payment of the Purchase Price, in whole
or in part, in Common Stock.

               At least three Business Days before the Company Notice Date, the
Company shall deliver an Officers' Certificate to the Trustee specifying:

               (i)    the manner of payment selected by the Company,

               (ii)   the information required by Section 3.08(e),

               (iii) if the Company elects to pay the Purchase Price, or a
               specified percentage thereof, in Common Stock, that the
               conditions to such manner of payment set forth in Section 3.08(d)
               have been or will be complied with, and

                                       23
<PAGE>   30

               (iv) whether the Company desires the Trustee to give the Company
               Notice required by Section 3.08(e).

               (c) Purchase with Cash. On each Purchase Date, at the option of
the Company, the Purchase Price of Securities in respect of which a Purchase
Notice pursuant to Section 3.08(a) has been given, or a specified percentage
thereof, may be paid by the Company with cash equal to the aggregate Purchase
Price of such Securities. If the Company elects to purchase Securities with
cash, the Company Notice, as provided in Section 3.08(e), shall be sent to
Holders (and to beneficial owners as required by applicable law) not less than
20 Business Days prior to such Purchase Date (the "Company Notice Date").

               (d) Payment by Issuance of Common Stock. On each Purchase Date,
at the option of the Company, the Purchase Price of Securities in respect of
which a Purchase Notice pursuant to Section 3.08(a) has been given, or a
specified percentage thereof, may be paid by the Company by the issuance of a
number of shares of Common Stock equal to the quotient obtained by dividing (i)
the amount of cash to which the Securityholders would have been entitled had the
Company elected to pay all or such specified percentage, as the case may be, of
the Purchase Price of such Securities in cash by (ii) the Market Price of a
share of Common Stock, subject to the next succeeding paragraph.

               The Company will not issue a fractional share of Common Stock in
payment of the Purchase Price. Instead the Company will pay cash for the current
market value of the fractional share. The current market value of a fraction of
a share shall be determined by multiplying the Market Price by such fraction and
rounding the product to the nearest whole cent. It is understood that if a
Holder elects to have more than one Security purchased, the number of shares of
Common Stock shall be based on the aggregate amount of Securities to be
purchased.

               If the Company elects to purchase the Securities by the issuance
of shares of Common Stock, the Company Notice, as provided in Section 3.08(e),
shall be sent to the Holders (and to beneficial owners as required by applicable
law) not later than the Company Notice Date.

               The Company's right to exercise its election to purchase the
Securities pursuant to Section 3.08 through the issuance of shares of Common
Stock shall be conditioned upon:

               (i) the Company's not having given its Company Notice of an
               election to pay entirely in cash and its giving of timely Company
               Notice of election to purchase all or a specified percentage of
               the Securities with Common Stock as provided herein;

               (ii) the registration of the shares of Common Stock to be issued
               in respect of the payment of the Purchase Price under the
               Securities Act of 1933, as amended (the "Securities Act"), or the
               Securities Exchange Act of 1934, as amended (the "Exchange Act"),
               in each case, if required;

               (iii) any necessary qualification or registration under
               applicable state securities laws or the availability of an
               exemption from such qualification and registration; and

                                       24
<PAGE>   31

               (iv) the receipt by the Trustee of an Officers' Certificate and
               an Opinion of Counsel each stating that (A) the terms of the
               issuance of the Common Stock are in conformity with this
               Indenture and (B) the shares of Common Stock to be issued by the
               Company in payment of the Purchase Price in respect of Securities
               have been duly authorized and, when issued and delivered pursuant
               to the terms of this Indenture in payment of the Purchase Price
               in respect of the Securities, will be validly issued, fully paid
               and non-assessable and, to the best of such counsel's knowledge,
               free from preemptive rights, and, in the case of such Officers'
               Certificate, stating that conditions (i), (ii) and (iii) above
               and the condition set forth in the second succeeding sentence
               have been satisfied and, in the case of such Opinion of Counsel,
               stating that conditions (ii) and (iii) above has been satisfied.

               Such Officers' Certificate shall also set forth the number of
shares of Common Stock to be issued for each $1,000 Principal Amount at Maturity
of Securities and the Sale Price of a share of Common Stock on each trading day
during the period commencing on the first trading day of the period during which
the Market Price is calculated and ending on the applicable Purchase Date. The
Company may pay the Purchase Price (or any portion thereof) in Common Stock only
if the information necessary to calculate the Market Price is published in a
daily newspaper of national circulation. If the foregoing conditions are not
satisfied with respect to a Holder or Holders prior to the close of business on
the Purchase Date and the Company has elected to purchase the Securities
pursuant to this Section 3.08 through the issuance of shares of Common Stock,
the Company shall pay the entire Purchase Price of the Securities of such Holder
or Holders in cash.

               The "Market Price" means the average of the Sale Prices of the
Common Stock for the five trading day period ending on (if the third Business
Day prior to the applicable Purchase Date is a trading day, or if not, then on
the last trading day prior to) the third Business Day prior to the applicable
Purchase Date, appropriately adjusted to take into account the occurrence,
during the period commencing on the first of such trading days during such five
trading day period and ending on such Purchase Date, of any event described in
Section 11.06, 11.07 or 11.08; subject, however, to the conditions set forth in
Sections 11.09 and 11.10.

               The "Sale Price" of the Common Stock on any date means the
closing per share sale price (or, if no closing sale price is reported, the
average of the bid and ask prices or, if more than one in either case, the
average of the average bid and average ask prices) on such date as reported in
the composite transactions for the principal United States securities exchange
on which the Common Stock is traded or, if the Common Stock is not listed on a
United States national or regional securities exchange, as reported by the
National Association of Securities Dealers Automated Quotation System.

               (e) Notice of Election. The Company's notice of election to
purchase with cash or Common Stock or any combination thereof shall be sent to
the Holders (and to beneficial owners as required by applicable law) in the
manner provided in Section 13.02 at the time specified in Section 3.08(c) or
(d), as applicable (the "Company Notice"). Such Company Notice shall state the
manner of payment elected and shall contain the following information:

                                       25
<PAGE>   32

               In the event the Company has elected to pay the Purchase Price
(or a specified percentage thereof) with Common Stock, the Company Notice shall:

               (1) state that each Holder will receive Common Stock with a
               Market Price determined as of a specified date prior to the
               Purchase Date equal to such specified percentage of the Purchase
               Price of the Securities held by such Holder (except any cash
               amount to be paid in lieu of fractional shares);

               (2) set forth the method of calculating the Market Price of the
               Common Stock; and

               (3) state that because the Market Price of Common Stock will be
               determined prior to the Purchase Date, Holders will bear the
               market risk with respect to the value of the Common Stock to be
               received from the date such Market Price is determined to the
               Purchase Date.

               In any case, each Company Notice shall include a form of Purchase
Notice to be completed by a Securityholder and shall state:

               (i) the Purchase Price and the Conversion Rate;

               (ii) the name and address of the Paying Agent and the Conversion
               Agent;

               (iii) that Securities as to which a Purchase Notice has been
               given may be converted pursuant to Article 11 hereof only if the
               applicable Purchase Notice has been withdrawn in accordance with
               the terms of this Indenture;

               (iv) that Securities must be surrendered to the Paying Agent to
               collect payment;

               (v) that the Purchase Price for any Security as to which a
               Purchase Notice has been given and not withdrawn will be paid
               promptly following the later of the Purchase Date and the time of
               surrender of such Security as described in (iv);

               (vi) the procedures the Holder must follow to exercise rights
               under Section 3.08 and a brief description of those rights;

               (vii)  briefly, the conversion rights of the Securities; and

               (viii) the procedures for withdrawing a Purchase Notice
               (including, without limitation, for a conditional withdrawal
               pursuant to the terms of Section 3.08(a)(1)(D) or Section 3.10).

               At the Company's request, the Trustee shall give such Company
Notice in the Company's name and at the Company's expense; provided, however,
that, in all cases, the text of such Company Notice shall be prepared by the
Company.

                                       26
<PAGE>   33

               Upon determination of the actual number of shares of Common Stock
to be issued for each $1,000 Principal Amount at Maturity of Securities, the
Company will publish such determination on the Company's Web site on the World
Wide Web or in a daily newspaper of national circulation.

               (f) Covenants of the Company. All shares of Common Stock
delivered upon purchase of the Securities shall be newly issued shares or
treasury shares, shall be duly authorized, validly issued, fully paid and
nonassessable and shall be free from preemptive rights and free of any lien or
adverse claim.

               The Company shall use its best efforts to list or cause to have
quoted any shares of Common Stock to be issued to purchase Securities on each
national securities exchange or over-the-counter or other domestic market on
which the Common Stock is then listed or quoted.

               (g) Procedure upon Purchase. The Company shall deposit cash (in
respect of a cash purchase under Section 3.08(c) or for fractional interests, as
applicable) or shares of Common Stock, or a combination thereof, as applicable,
at the time and in the manner as provided in Section 3.11, sufficient to pay the
aggregate Purchase Price of all Securities to be purchased pursuant to this
Section 3.08. As soon as practicable after the Purchase Date, the Company shall
deliver to each Holder entitled to receive Common Stock through the Paying
Agent, a certificate for the number of full shares of Common Stock issuable in
payment of the Purchase Price and cash in lieu of any fractional interests. The
person in whose name the certificate for Common Stock is registered shall be
treated as a holder of record of shares of Common Stock on the Business Day
following the Purchase Date. Subject to Section 3.08(d), no payment or
adjustment will be made for dividends on the Common Stock the record date for
which occurred on or prior to the Purchase Date.

               (h) Taxes. If a Holder of a Security is paid in Common Stock, the
Company shall pay any documentary, stamp or similar issue or transfer tax due on
such issue of shares of Common Stock. However, the Holder shall pay any such tax
which is due because the Holder requests the shares of Common Stock to be issued
in a name other than the Holder's name. The Paying Agent may refuse to deliver
the certificates representing the Common Stock being issued in a name other than
the Holder's name until the Paying Agent receives a sum sufficient to pay any
tax which will be due because the shares of Common Stock are to be issued in a
name other than the Holder's name. Nothing herein shall preclude any income tax
withholding required by law or regulations.

               SECTION 3.09 Purchase of Securities at Option of the Holder upon
Change in Control. (a) If on or prior to November 1, 2003 there shall have
occurred a Change in Control, Securities shall be purchased by the Company, at
the option of the Holder thereof, at the purchase price specified in paragraph 6
of the Securities (the "Change in Control Purchase Price"), as of the date that
is 35 Business Days after the occurrence of the Change in Control (the "Change
in Control Purchase Date"), subject to satisfaction by or on behalf of the
Holder of the requirements set forth in Section 3.09(c).

               A "Change in Control" shall be deemed to have occurred at such
time as either of the following events shall occur:

                                       27
<PAGE>   34

               (i) There shall be consummated any consolidation or merger of the
               Company pursuant to which the Common Stock would be converted
               into cash, securities or other property, in each case other than
               a consolidation or merger of the Company in which the holders of
               the Common Stock immediately prior to the consolidation or merger
               have, directly or indirectly, at least a majority of the total
               voting power in the aggregate of all classes of capital stock of
               the continuing or surviving corporation immediately after such
               consolidation or merger; or

               (ii) There is a report filed on Schedule 13D or 14D-1 (or any
               successor schedule, form or report) pursuant to the Exchange Act,
               disclosing that any person (for the purposes of this Section 3.09
               only, as the term "person" is used in Section 13(d)(3) or Section
               14(d)(2) of the Exchange Act) has become the beneficial owner (as
               the term "beneficial owner" is defined under Rule 13d-3 or any
               successor rule or regulation promulgated under the Exchange Act)
               of 50% or more of the voting power of the Common Stock then
               outstanding; provided, however, that a person shall not be deemed
               beneficial owner of, or to own beneficially, (A) any securities
               tendered pursuant to a tender or exchange offer made by or on
               behalf of such person or any of such person's Affiliates or
               Associates until such tendered securities are accepted for
               purchase or exchange thereunder, or (B) any securities if such
               beneficial ownership (1) arises solely as a result of a revocable
               proxy delivered in response to a proxy or consent solicitation
               made pursuant to the applicable rules and regulations under the
               Exchange Act, and (2) is not also then reportable on Schedule 13D
               (or any successor schedule) under the Exchange Act.

Notwithstanding the foregoing provisions of this Section 3.09, a Change in
Control shall not be deemed to have occurred by virtue of the Company, any
Subsidiary, any employee stock ownership plan or any other employee benefit plan
of the Company or any Subsidiary, or any person holding Common Stock for or
pursuant to the terms of any such employee benefit plan, filing or becoming
obligated to file a report under or in response to Schedule 13D or Schedule
14D-1 (or any successor schedule, form or report) under the Exchange Act
disclosing beneficial ownership by it of shares of Common Stock, whether in
excess of 50% or otherwise.

               "Associate" shall have the meaning ascribed to such term in Rule
12b-2 of the General Rules and Regulations under the Exchange Act, as in effect
on the date hereof.

               (b) Within 15 Business Days after the occurrence of a Change in
Control, the Company shall mail a written notice of Change in Control by
first-class mail to the Trustee and to each Holder (and to beneficial owners as
required by applicable law). The notice shall include a form of Change in
Control Purchase Notice to be completed by the Securityholder and shall state:

               (1) briefly, the events causing a Change in Control and the date
               of such Change in Control;

               (2) the date by which the Change in Control Purchase Notice
               pursuant to this Section 3.09 must be given;

                                       28
<PAGE>   35

               (3) the Change in Control Purchase Date;

               (4) the Change in Control Purchase Price;

               (5) the name and address of the Paying Agent and the Conversion
               Agent;

               (6) the Conversion Rate and any adjustments thereto;

               (7) that Securities as to which a Change in Control Purchase
               Notice has been given may be converted pursuant to Article 11
               hereof only if the Change in Control Purchase Notice has been
               withdrawn in accordance with the terms of this Indenture;

               (8) that Securities must be surrendered to the Paying Agent to
               collect payment;

               (9) that the Change in Control Purchase Price for any Security as
               to which a Change in Control Purchase Notice has been duly given
               and not withdrawn will be paid promptly following the later of
               the Change in Control Purchase Date and the time of surrender of
               such Security as described in (8);

               (10) briefly, the procedures the Holder must follow to exercise
               rights under this Section 3.09;

               (11) briefly, the conversion rights of the Securities; and

               (12) the procedures for withdrawing a Change in Control Purchase
               Notice.

               (c) A Holder may exercise its rights specified in Section 3.09(a)
upon delivery of a written notice of purchase (a "Change in Control Purchase
Notice") to the Paying Agent at any time prior to the close of business on the
Change in Control Purchase Date, stating:

               (1) the identifying number of the Security which the Holder will
               deliver to be purchased;

               (2) the portion of the Principal Amount at Maturity of the
               Security which the Holder will deliver to be purchased, which
               portion must be $1,000 or an integral multiple thereof; and

               (3) that such Security shall be purchased pursuant to the terms
               and conditions specified in paragraph 6 of the Securities.

               The delivery of such Security to the Paying Agent prior to, on or
after the Change in Control Purchase Date (together with all necessary
endorsements) at the offices of the Paying Agent shall be a condition to the
receipt by the Holder of the Change in Control Purchase Price therefor;
provided, however, that such Change in Control Purchase Price shall be so paid
pursuant to this Section 3.09 only if the Security so delivered to the Paying
Agent shall conform

                                       29
<PAGE>   36

in all respects to the description thereof set forth in the related Change in
Control Purchase Notice.

               The Company shall purchase from the Holder thereof, pursuant to
this Section 3.09, a portion of a Security if the Principal Amount at Maturity
of such portion is $1,000 or an integral multiple of $1,000. Provisions of this
Indenture that apply to the purchase of all of a Security also apply to the
purchase of such portion of such Security.

               Any purchase by the Company contemplated pursuant to the
provisions of this Section 3.09 shall be consummated by the delivery of the
consideration to be received by the Holder promptly following the later of the
Change in Control Purchase Date and the time of delivery of the Security to the
Paying Agent in accordance with this Section 3.09.

               Notwithstanding anything herein to the contrary, any Holder
delivering to the Paying Agent the Change in Control Purchase Notice
contemplated by this Section 3.09(c) shall have the right to withdraw such
Change in Control Purchase Notice at any time prior to the close of business on
the Change in Control Purchase Date by delivery of a written notice of
withdrawal to the Paying Agent in accordance with Section 3.10.

               The Paying Agent shall promptly notify the Company of the receipt
by it of any Change in Control Purchase Notice or written withdrawal thereof.

               SECTION 3.10 Effect of Purchase Notice or Change in Control
Purchase Notice. Upon receipt by the Paying Agent of the Purchase Notice or
Change in Control Purchase Notice specified in Section 3.08(a) or Section
3.09(c), as applicable, the Holder of the Security in respect of which such
Purchase Notice or Change in Control Purchase Notice, as the case may be, was
given shall (unless such Purchase Notice or Change in Control Purchase Notice is
withdrawn as specified in the following two paragraphs) thereafter be entitled
to receive solely the Purchase Price or Change in Control Purchase Price, as the
case may be, with respect to such Security. Such Purchase Price or Change in
Control Purchase Price shall be paid to such Holder, subject to receipts of
funds and/or securities by the Paying Agent, promptly following the later of (x)
the Purchase Date or the Change in Control Purchase Date, as the case may be,
with respect to such Security (provided the conditions in Section 3.08(a) or
Section 3.09(c), as applicable, have been satisfied) and (y) the time of
delivery of such Security to the Paying Agent by the Holder thereof in the
manner required by Section 3.08(a) or Section 3.09(c), as applicable. Securities
in respect of which a Purchase Notice or Change in Control Purchase Notice, as
the case may be, has been given by the Holder thereof may not be converted
pursuant to Article 11 hereof on or after the date of the delivery of such
Purchase Notice or Change in Control Purchase Notice, as the case may be, unless
such Purchase Notice or Change in Control Purchase Notice, as the case may be,
has first been validly withdrawn as specified in the following two paragraphs.

               A Purchase Notice or Change in Control Purchase Notice, as the
case may be, may be withdrawn by means of a written notice of withdrawal
delivered to the office of the Paying Agent in accordance with the Purchase
Notice or Change in Control Purchase Notice, as the case may be, at any time
prior to the close of business on the Purchase Date or the Change in Control
Purchase Date, as the case may be, specifying:

                                       30
<PAGE>   37

               (1) the identifying number of the Security in respect of which
               such notice of withdrawal is being submitted,

               (2) the Principal Amount at Maturity of the Security with respect
               to which such notice of withdrawal is being submitted, and

               (3) the Principal Amount at Maturity, if any, of such Security
               which remains subject to the original Purchase Notice or Change
               in Control Purchase Notice, as the case may be, and which has
               been or will be delivered for purchase by the Company.

               A written notice of withdrawal of a Purchase Notice may be in the
form set forth in the preceding paragraph or may be in the form of (i) a
conditional withdrawal contained in a Purchase Notice pursuant to the terms of
Section 3.08(a)(1)(D) or (ii) a conditional withdrawal containing the
information set forth in Section 3.08(a)(1)(D) and the preceding paragraph and
contained in a written notice of withdrawal delivered to the Paying Agent as set
forth in the preceding paragraph.

               There shall be no purchase of any Securities pursuant to Section
3.08 (other than through the issuance of Common Stock in payment of the Purchase
Price, including cash in lieu of fractional shares) or 3.09 if there has
occurred (prior to, on or after, as the case may be, the giving, by the Holders
of such Securities, of the required Purchase Notice or Change in Control
Purchase Notice, as the case may be) and is continuing an Event of Default
(other than a default in the payment of the Purchase Price or Change in Control
Purchase Price, as the case may be, with respect to such Securities). The Paying
Agent will promptly return to the respective Holders thereof any Securities (x)
with respect to which a Purchase Notice or Change in Control Purchase Notice, as
the case may be, has been withdrawn in compliance with this Indenture, or (y)
held by it during the continuance of an Event of Default (other than a default
in the payment of the Purchase Price or Change in Control Purchase Price, as the
case may be, with respect to such Securities) in which case, upon such return,
the Purchase Notice or Change in Control Purchase Notice with respect thereto
shall be deemed to have been withdrawn.

               SECTION 3.11 Deposit of Purchase Price or Change in Control
Purchase Price. Prior to 11:30 a.m. (local time in The City of New York) on the
Business Day following the Purchase Date or the Change in Control Purchase Date,
as the case may be, the Company shall deposit with the Trustee or with the
Paying Agent (or, if the Company or a Subsidiary or an Affiliate of either of
them is acting as the Paying Agent, shall segregate and hold in trust as
provided in Section 2.04) an amount of money (in immediately available funds if
deposited on such Business Day) or Common Stock, if permitted hereunder,
sufficient to pay the aggregate Purchase Price or Change in Control Purchase
Price, as the case may be, of all the Securities or portions thereof which are
to be purchased as of the Purchase Date or Change in Control Purchase Date, as
the case may be.

               SECTION 3.12 Securities Purchased in Part. Any Security which is
to be purchased only in part shall be surrendered at the office of the Paying
Agent (with, if the Company or the Trustee so requires, due endorsement by, or a
written instrument of transfer in form satisfactory to the Company and the
Trustee duly executed by, the Holder thereof or such

                                       31
<PAGE>   38

Holder's attorney duly authorized in writing) and the Company shall execute and
the Trustee shall authenticate and the Registrar shall deliver to the Holder of
such Security, without service charge, a new Security or Securities, of any
authorized denomination as requested by such Holder in aggregate Principal
Amount at Maturity equal to, and in exchange for, the portion of the Principal
Amount at Maturity of the Security so surrendered which is not purchased.

               SECTION 3.13 Covenant to Comply With Securities Laws Upon
Purchase of Securities. In connection with any offer to purchase or purchase of
Securities under Section 3.08 or 3.09 hereof (provided that such offer or
purchase constitutes an "issuer tender offer" for purposes of Rule 13e-4 (which
term, as used herein, includes any successor provision thereto) under the
Exchange Act at the time of such offer or purchase), the Company shall (i)
comply with Rule 13e-4 and Rule 14e-1 under the Exchange Act, (ii) file the
related Schedule 13E-4 (or any successor schedule, form or report) under the
Exchange Act, and (iii) otherwise comply with all Federal and state securities
laws so as to permit the rights and obligations under Sections 3.08 and 3.09 to
be exercised in the time and in the manner specified in Sections 3.08 and 3.09.

               SECTION 3.14 Repayment to the Company. The Trustee and the Paying
Agent shall return to the Company any cash or shares of Common Stock that remain
unclaimed as provided in paragraph 13 of the Securities, held by them for the
payment of the Purchase Price or Change in Control Purchase Price, as the case
may be; provided, however, that to the extent that the aggregate amount of cash
or shares of Common Stock deposited by the Company pursuant to Section 3.11
exceeds the aggregate Purchase Price or Change in Control Purchase Price, as the
case may be, of the Securities or portions thereof which the Company is
obligated to purchase as of the Purchase Date or Change in Control Purchase
Date, as the case may be, then promptly after the Business Day following the
Purchase Date or Change in Control Purchase Date, as the case may be, the
Trustee shall return any such excess to the Company.

                                    ARTICLE 4

                                    COVENANTS

               SECTION 4.01 Payment of Securities. The Company shall promptly
make all payments in respect of the Securities on the dates and in the manner
provided in the Securities or pursuant to this Indenture. Principal Amount at
Maturity, Restated Principal Amount, Issue Price plus accrued Original Issue
Discount, Redemption Price, Purchase Price, Change in Control Purchase Price and
interest, if any, shall be considered paid on the applicable date due if on such
date (or, in the case of a Purchase Price or Change in Control Purchase Price,
on the Business Day following the applicable Purchase Date or Change in Control
Purchase Date, as the case may be) the Trustee or the Paying Agent holds, in
accordance with this Indenture, money or securities, if permitted hereunder,
sufficient to pay all such amounts then due.

               The Company shall, to the extent permitted by law, pay interest
on overdue amounts at the rate per annum set forth in paragraph 1 of the
Securities, compounded semiannually, which interest shall accrue from the date
such overdue amount was originally due to the date payment of such amount,
including interest thereon, has been made or duly provided for. All such
interest shall be payable on demand. The accrual of such interest on overdue

                                       32
<PAGE>   39

amounts shall be in lieu of, and not in addition to, the continued accrual of
Original Issue Discount.

               SECTION 4.02 SEC and Other Reports. The Company shall file with
the Trustee, within 15 days after it files such annual and quarterly reports,
information, documents and other reports with the SEC, copies of its annual
report and of the information, documents and other reports (or copies of such
portions of any of the foregoing as the SEC may by rules and regulations
prescribe) which the Company is required to file with the SEC pursuant to
Section 13 or 15(d) of the Exchange Act. In the event the Company is at any time
no longer subject to the reporting requirements of Section 13 or 15(d) of the
Exchange Act, it shall continue to provide the Trustee with reports containing
substantially the same information as would have been required to be filed with
the SEC had the Company continued to have been subject to such reporting
requirements. In such event, such reports shall be provided at the times the
Company would have been required to provide reports had it continued to have
been subject to such reporting requirements. The Company also shall comply with
the other provisions of TIA Section 314(a).

               SECTION 4.03 Compliance Certificate. The Company shall deliver to
the Trustee within 120 days after the end of each fiscal year of the Company
(beginning with the fiscal year ending on December 31, 2000) an Officers'
Certificate stating whether or not to the best knowledge of the signers thereof
the Company is in default in the performance and observance of any of the terms,
provisions and conditions of this Indenture (without regard to any period of
grace or requirement of notice provided hereunder) and if the Company shall be
in default, specifying all such defaults and the nature and status thereof of
which they may have knowledge.

               SECTION 4.04 Further Instruments and Acts. Upon request of the
Trustee, the Company will execute and deliver such further instruments and do
such further acts as may be reasonably necessary or proper to carry out more
effectively the purposes of this Indenture.

               SECTION 4.05 Maintenance of Office or Agency. The Company will
maintain in the Borough of Manhattan, The City of New York, an office or agency
of the Trustee, Registrar, Paying Agent and Conversion Agent where Securities
may be presented or surrendered for payment, where Securities may be surrendered
for registration of transfer, exchange, purchase, redemption or conversion and
where notices and demands to or upon the Company in respect of the Securities
and this Indenture may be served. The office of U.S. Bank Trust National
Association, located at 100 Wall Street, 16th Floor, New York, New York 10005
(Attention: Corporate Trust Administration - Allergan, Inc., Liquid Yield Option
Notes due 2020 (Zero Coupon - Subordinated)), shall initially be such office or
agency for all of the aforesaid purposes. The Company shall give prompt written
notice to the Trustee of the location, and of any change in the location, of any
such office or agency (other than a change in the location of the office of the
Trustee). If at any time the Company shall fail to maintain any such required
office or agency or shall fail to furnish the Trustee with the address thereof,
such presentations, surrenders, notices and demands may be made or served at the
address of the Trustee set forth in Section 13.02.

                                       33
<PAGE>   40

               The Company may also from time to time designate one or more
other offices or agencies where the Securities may be presented or surrendered
for any or all such purposes and may from time to time rescind such
designations; provided, however, that no such designation or rescission shall in
any manner relieve the Company of its obligation to maintain an office or agency
in the Borough of Manhattan, the City of New York, for such purposes.

               SECTION 4.06 Delivery of Certain Information. At any time when
the Company is not subject to Section 13 or 15(d) of the Exchange Act, upon the
request of a holder or any beneficial holder of Securities or shares of Common
Stock issued upon conversion thereof, the Company will promptly furnish or cause
to be furnished Rule 144A Information (as defined below) to such Holder or any
beneficial holder of Securities or holder of shares of Common Stock issued upon
conversion of Securities, or to a prospective purchaser of any such security
designated by any such holder, as the case may be, to the extent required to
permit compliance by such Holder or holder with Rule 144A under the Securities
Act in connection with the resale of any such security. "Rule 144A Information"
shall be such information as is specified pursuant to Rule 144A(d)(4) under the
Securities Act.

                                    ARTICLE 5

                              SUCCESSOR CORPORATION

               SECTION 5.01 When Company May Merge or Transfer Assets. The
Company shall not consolidate with or merge with or into any other person or
convey, transfer or lease its properties and assets substantially as an entirety
to any person, unless:

               (a) either (1) the Company shall be the continuing corporation or
(2) the person (if other than the Company) formed by such consolidation or into
which the Company is merged or the person which acquires by conveyance, transfer
or lease the properties and assets of the Company substantially as an entirety
(i) shall be organized and validly existing under the laws of (x) the United
States or any State thereof or the District of Columbia, (y) any member country
of the European Union, or (z) if such merger, consolidation or other transaction
would not impair the rights of Holders, any other country, and (ii) shall
expressly assume, by an indenture supplemental hereto, executed and delivered to
the Trustee, in form satisfactory to the Trustee, all of the obligations of the
Company under the Securities and this Indenture;

               (b) immediately after giving effect to such transaction, no
Default shall have occurred and be continuing; and

               (c) the Company shall have delivered to the Trustee an Officers'
Certificate and an Opinion of Counsel, each stating that such consolidation,
merger, conveyance, transfer or lease and, if a supplemental indenture is
required in connection with such transaction, such supplemental indenture,
comply with this Article 5 and that all conditions precedent herein provided for
relating to such transaction have been satisfied.

               For purposes of the foregoing, the transfer (by lease,
assignment, sale or otherwise) of the properties and assets of one or more
Subsidiaries (other than to the Company or another Subsidiary), which, if such
assets were owned by the Company, would constitute all or

                                       34
<PAGE>   41

substantially all of the properties and assets of the Company, shall be deemed
to be the transfer of all or substantially all of the properties and assets of
the Company.

               The successor person formed by such consolidation or into which
the Company is merged or the successor person to which such conveyance, transfer
or lease is made shall succeed to, and be substituted for, and may exercise
every right and power of, the Company under this Indenture with the same effect
as if such successor had been named as the Company herein; and thereafter,
except in the case of a lease and obligations the Company may have under a
supplemental indenture pursuant to Section 11.14, the Company shall be
discharged from all obligations and covenants under this Indenture and the
Securities. Subject to Section 9.06, the Company, the Trustee and the successor
person shall enter into a supplemental indenture to evidence the succession and
substitution of such successor person and such discharge and release of the
Company.

                                    ARTICLE 6

                              DEFAULTS AND REMEDIES

               SECTION 6.01 Events of Default. An "Event of Default" occurs if:

               (1) after exercise of its option pursuant to Section 10.01 hereof
               following a Tax Event, the Company defaults in the payment of
               interest upon any Security when such interest becomes due and
               payable, and such default continues for a period of 30 days;

               (2) the Company defaults in the payment of the Principal Amount
               at Maturity (or, if the Securities have been converted to
               semiannual coupon notes following a Tax Event pursuant to Article
               10, the Restated Principal Amount), Issue Price plus accrued
               Original Issue Discount, Redemption Price, Purchase Price or
               Change in Control Purchase Price on any Security when the same
               becomes due and payable at its Stated Maturity, upon redemption,
               upon declaration, when due for purchase by the Company or
               otherwise;

               (3) the Company fails to comply with any of its agreements in the
               Securities or this Indenture (other than those referred to in
               clauses (1) and (2) above) and such failure continues for 90 days
               after receipt by the Company of a Notice of Default;

               (4) (a) failure of the Company to make any payment by the end of
               any applicable grace period after maturity of Debt in an amount
               in excess of $75,000,000 and continuance of such failure, or (b)
               the acceleration of Debt in an amount in excess of $75,000,000
               because of a default with respect to such Debt without such Debt
               having been discharged or such acceleration having been cured,
               waived, rescinded or annulled, in the case of (a) or (b) above,
               for a period of 30 days after receipt by the Company of a Notice
               of Default; provided, however, that if any such failure or
               acceleration referred to in (a) or (b) above

                                       35
<PAGE>   42

               shall cease or be cured, waived, rescinded or annulled, then the
               Event of Default by reason thereof shall be deemed not to have
               occurred; or

               (5) the Company pursuant to or under or within the meaning of any
               Bankruptcy Law:

                      (A) commences a voluntary case or proceeding;

                      (B) consents to the entry of an order for relief against
                      it in an involuntary case or proceeding or the
                      commencement of any case against it;

                      (C) consents to the appointment of a Custodian of it or
                      for any substantial part of its property;

                      (D) makes a general assignment for the benefit of its
                      creditors;

                      (E) files a petition in bankruptcy or answer or consent
                      seeking reorganization or relief; or

                      (F) consents to the filing of such petition or the
                      appointment of or taking possession by a Custodian; or

               (6) a court of competent jurisdiction enters an order or decree
               under any Bankruptcy Law that:

                      (A) is for relief against the Company in an involuntary
                      case or proceeding, or adjudicates the Company insolvent
                      or bankrupt;

                      (B) appoints a Custodian of the Company or for any
                      substantial part of its property; or

                      (C) orders the winding up or liquidation of the Company;

        and the order or decree remains unstayed and in effect for 60 days.

               "Bankruptcy Law" means Title 11, United States Code, or any
similar Federal or state law for the relief of debtors.

               "Custodian" means any receiver, trustee, assignee, liquidator,
custodian or similar official under any Bankruptcy Law.

               A Default under clause (3) or clause (4) above is not an Event of
Default until the Trustee notifies the Company, or the Holders of at least 25%
in aggregate Principal Amount at Maturity of the Securities at the time
outstanding notify the Company and the Trustee, of the Default and the Company
does not cure such Default (and such Default is not waived) within the time
specified in clause (3) or clause (4) above after actual receipt of such notice.
Any such

                                       36
<PAGE>   43

notice must specify the Default, demand that it be remedied and state that such
notice is a "Notice of Default".

               The Company shall deliver to the Trustee, within 30 days after it
becomes aware of the occurrence thereof, written notice of any event which with
the giving of notice or the lapse of time, or both, would become an Event of
Default under clause (3) or clause (4) above, its status and what action the
Company is taking or proposes to take with respect thereto.

               SECTION 6.02 Acceleration. If an Event of Default (other than an
Event of Default specified in Section 6.01(5) or (6)) occurs and is continuing,
the Trustee by Notice to the Company, or the Holders of at least 25% in
aggregate Principal Amount at Maturity of the Securities at the time outstanding
by notice to the Company and the Trustee, may declare the Issue Price plus
accrued Original Issue Discount through the date of declaration on all the
Securities to be immediately due and payable. Upon such a declaration, such
Issue Price plus accrued Original Issue Discount shall be due and payable
immediately. If an Event of Default specified in Section 6.01(5) or (6) occurs
and is continuing, the Issue Price plus accrued Original Issue Discount on all
the Securities shall become and be immediately due and payable without any
declaration or other act on the part of the Trustee or any Securityholders. The
Holders of a majority in aggregate Principal Amount at Maturity of the
Securities at the time outstanding, by notice to the Trustee (and without notice
to any other Securityholder) may rescind an acceleration and its consequences if
the rescission would not conflict with any judgment or decree and if all
existing Events of Default have been cured or waived except nonpayment of the
Issue Price plus accrued Original Issue Discount that have become due solely as
a result of acceleration and if all amounts due to the Trustee under Section
7.07 have been paid. No such rescission shall affect any subsequent Default or
impair any right consequent thereto.

               SECTION 6.03 Other Remedies. If an Event of Default occurs and is
continuing, the Trustee may pursue any available remedy to collect the payment
of the Issue Price plus accrued Original Issue Discount on the Securities or to
enforce the performance of any provision of the Securities or this Indenture.

               The Trustee may maintain a proceeding even if the Trustee does
not possess any of the Securities or does not produce any of the Securities in
the proceeding. A delay or omission by the Trustee or any Securityholder in
exercising any right or remedy accruing upon an Event of Default shall not
impair the right or remedy or constitute a waiver of, or acquiescence in, the
Event of Default. No remedy is exclusive of any other remedy. All available
remedies are cumulative.

               SECTION 6.04 Waiver of Past Defaults. The Holders of a majority
in aggregate Principal Amount at Maturity of the Securities at the time
outstanding, by notice to the Trustee (and without notice to any other
Securityholder), may waive an existing Default and its consequences except (1)
an Event of Default described in Section 6.01(1) or (2), (2) a Default in
respect of a provision that under Section 9.02 cannot be amended without the
consent of each Securityholder affected or (3) a Default which constitutes a
failure to convert any Security in accordance with the terms of Article 11. When
a Default is waived, it is deemed cured, but no such waiver shall extend to any
subsequent or other Default or impair any consequent right. This

                                       37
<PAGE>   44

Section 6.04 shall be in lieu of Section 316(a)1(B) of the TIA and such Section
316(a)1(B) is hereby expressly excluded from this Indenture, as permitted by the
TIA.

               SECTION 6.05 Control by Majority. The Holders of a majority in
aggregate Principal Amount at Maturity of the Securities at the time outstanding
may direct the time, method and place of conducting any proceeding for any
remedy available to the Trustee or of exercising any trust or power conferred on
the Trustee. However, the Trustee may refuse to follow any direction that
conflicts with law or this Indenture or that the Trustee determines in good
faith is unduly prejudicial to the rights of other Securityholders or would
involve the Trustee in personal liability unless the Trustee is offered
indemnity satisfactory to it. This Section 6.05 shall be in lieu of Section
316(a)1(A) of the TIA and such Section 316(a)1(A) is hereby expressly excluded
from this Indenture, as permitted by the TIA.

               SECTION 6.06 Limitation on Suits. A Securityholder may not pursue
any remedy with respect to this Indenture or the Securities unless:

               (1) the Holder gives to the Trustee written notice stating that
               an Event of Default is continuing;

               (2) the Holders of at least 25% in aggregate Principal Amount at
               Maturity of the Securities at the time outstanding make a written
               request to the Trustee to pursue the remedy;

               (3) such Holder or Holders offer to the Trustee reasonable
               security or indemnity satisfactory to the Trustee against any
               loss, liability or expense;

               (4) the Trustee does not comply with the request within 60 days
               after receipt of such notice, request and offer of security or
               indemnity; and

               (5) the Holders of a majority in aggregate Principal Amount at
               Maturity of the Securities at the time outstanding do not give
               the Trustee a direction inconsistent with the request during such
               60-day period.

               A Securityholder may not use this Indenture to prejudice the
rights of any other Securityholder or to obtain a preference or priority over
any other Securityholder.

               SECTION 6.07 Rights of Holders to Receive Payment.
Notwithstanding any other provision of this Indenture, the right of any Holder
to receive payment of the Principal Amount at Maturity (or if the Securities
have been converted to semiannual coupon notes following a Tax Event pursuant to
Article 10, the Restated Principal Amount), Issue Price plus accrued Original
Issue Discount, Redemption Price, Purchase Price, Change in Control Purchase
Price or interest, if any, in respect of the Securities held by such Holder, on
or after the respective due dates expressed in the Securities or any Redemption
Date, and to convert the Securities in accordance with Article 11, or to bring
suit for the enforcement of any such payment on or after such respective dates
or the right to convert, shall not be impaired or affected adversely without the
consent of such Holder.

                                       38
<PAGE>   45

               SECTION 6.08 Collection Suit by Trustee. If an Event of Default
described in Section 6.01(1) or (2) occurs and is continuing, the Trustee may
recover judgment in its own name and as trustee of an express trust against the
Company for the whole amount owing with respect to the Securities and the
amounts provided for in Section 7.07.

               SECTION 6.09 Trustee May File Proofs of Claim. In case of the
pendency of any receivership, insolvency, liquidation, bankruptcy,
reorganization, arrangement, adjustment, composition or other judicial
proceeding relative to the Company or any other obligor upon the Securities or
the property of the Company or of such other obligor or their creditors, the
Trustee (irrespective of whether the Principal Amount at Maturity, Issue Price
plus accrued Original Issue Discount, Redemption Price, Purchase Price, Change
in Control Purchase Price or interest, if any, in respect of the Securities
shall then be due and payable as therein expressed or by declaration or
otherwise and irrespective of whether the Trustee shall have made any demand on
the Company for the payment of any such amount) shall be entitled and empowered,
by intervention in such proceeding or otherwise,

               (a) to file and prove a claim for the whole amount of the
               Principal Amount at Maturity, Issue Price plus accrued Original
               Issue Discount, Redemption Price, Purchase Price, Change in
               Control Purchase Price, or interest, if any, to participate as a
               member, voting or otherwise, of any official committee appointed
               for such matter, and to file such other papers or documents as
               may be necessary or advisable in order to have the claims of the
               Trustee (including any claim for the reasonable compensation,
               expenses, disbursements and advances of the Trustee, its agents
               and counsel or any other amounts due the Trustee under Section
               7.07) and of the Holders allowed in such judicial proceeding, and

               (b) to collect and receive any moneys or other property payable
               or deliverable on any such claims and to distribute the same;

and any custodian, receiver, assignee, trustee, liquidator, sequestrator or
similar official in any such judicial proceeding is hereby authorized by each
Holder to make such payments to the Trustee and, in the event that the Trustee
shall consent to the making of such payments directly to the Holders, to pay the
Trustee any amount due it for the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel, and any other
amounts due the Trustee under Section 7.07.

               Nothing herein contained shall be deemed to authorize the Trustee
to authorize or consent to or accept or adopt on behalf of any Holder any plan
of reorganization, arrangement, adjustment or composition affecting the
Securities or the rights of any Holder thereof, or to authorize the Trustee to
vote in respect of the claim of any Holder in any such proceeding.

               SECTION 6.10 Priorities. If the Trustee collects any money
pursuant to this Article 6, it shall pay out the money in the following order:

               FIRST: to the Trustee for amounts due under Section 7.07;

               SECOND: to Securityholders for amounts due and unpaid on the
               Securities for the Principal Amount at Maturity, Issue Price plus
               accrued Original Issue

                                       39
<PAGE>   46

               Discount, Redemption Price, Purchase Price, Change in Control
               Purchase Price or interest, if any, as the case may be, ratably,
               without preference or priority of any kind, according to such
               amounts due and payable on the Securities; and

               THIRD: the balance, if any, to the Company.

               The Trustee may fix a record date and payment date for any
payment to Securityholders pursuant to this Section 6.10. At least 15 days
before such record date, the Trustee shall mail to each Securityholder and the
Company a notice that states the record date, the payment date and the amount to
be paid.

               SECTION 6.11 Undertaking for Costs. In any suit for the
enforcement of any right or remedy under this Indenture or in any suit against
the Trustee for any action taken or omitted by it as Trustee, a court in its
discretion may require the filing by any party litigant (other than the Trustee)
in the suit of an undertaking to pay the costs of the suit, and the court in its
discretion may assess reasonable costs, including reasonable attorneys' fees,
against any party litigant in the suit, having due regard to the merits and good
faith of the claims or defenses made by the party litigant. This Section 6.11
does not apply to a suit by the Trustee, a suit by a Holder pursuant to Section
6.07 or a suit by Holders of more than 10% in aggregate Principal Amount at
Maturity of the Securities at the time outstanding. This Section 6.11 shall be
in lieu of Section 315(e) of the TIA and such Section 315(e) is hereby expressly
excluded from this Indenture, as permitted by the TIA.

               SECTION 6.12 Waiver of Stay, Extension or Usury Laws. The Company
covenants (to the extent that it may lawfully do so) that it will not at any
time insist upon, or plead, or in any manner whatsoever claim or take the
benefit or advantage of, any stay or extension law or any usury or other law
wherever enacted, now or at any time hereafter in force, which would prohibit or
forgive the Company from paying all or any portion of the Principal Amount at
Maturity, Issue Price plus accrued Original Issue Discount, Redemption Price,
Purchase Price or Change in Control Purchase Price in respect of Securities, or
any interest on such amounts, as contemplated herein, or which may affect the
covenants or the performance of this Indenture; and the Company (to the extent
that it may lawfully do so) hereby expressly waives all benefit or advantage of
any such law, and covenants that it will not hinder, delay or impede the
execution of any power herein granted to the Trustee, but will suffer and permit
the execution of every such power as though no such law had been enacted.

                                    ARTICLE 7

                                     TRUSTEE

               SECTION 7.01 Duties of Trustee. (a) If an Event of Default has
occurred and is continuing, the Trustee shall exercise the rights and powers
vested in it by this Indenture and use the same degree of care and skill in its
exercise as a prudent person would exercise or use under the circumstances in
the conduct of his own affairs.

                                       40
<PAGE>   47

               (b) Except during the continuance of an Event of Default:

               (1) the Trustee need perform only those duties that are
               specifically set forth in this Indenture and no others; and

               (2) in the absence of bad faith on its part, the Trustee may
               conclusively rely, as to the truth of the statements and the
               correctness of the opinions expressed therein, upon certificates
               or opinions furnished to the Trustee and conforming to the
               requirements of this Indenture. However, the Trustee shall
               examine the certificates and opinions to determine whether or not
               they conform to the requirements of this Indenture.

This Section 7.01(b) shall be in lieu of Section 3.15(a) of the TIA and such
Section 315(a) is hereby expressly excluded from this Indenture, as permitted by
the TIA.

               (c) The Trustee may not be relieved from liability for its own
negligent action, its own negligent failure to act or its own willful
misconduct, except that:

               (1) this paragraph (c) does not limit the effect of paragraph (b)
               of this Section 7.01;

               (2) the Trustee shall not be liable for any error of judgment
               made in good faith by a Responsible Officer unless it is proved
               that the Trustee was negligent in ascertaining the pertinent
               facts; and

               (3) the Trustee shall not be liable with respect to any action it
               takes or omits to take in good faith in accordance with a
               direction received by it pursuant to Section 6.05.

Subparagraphs (c)(1), (2) and (3) shall be in lieu of Sections 315(d)(1),
315(d)(2) and 315(d)(3) of the TIA and such Sections 315(d)(1), 315(d)(2) and
315(d)(3) are hereby expressly excluded from this Indenture, as permitted by the
TIA.

               (d) Every provision of this Indenture that in any way relates to
the Trustee is subject to paragraphs (a), (b), (c) and (e) of this Section 7.01.

               (e) The Trustee may refuse to perform any duty or exercise any
right or power or extend or risk its own funds or otherwise incur any financial
liability unless it receives indemnity satisfactory to it against any loss,
liability or expense.

               (f) Money held by the Trustee in trust hereunder need not be
segregated from other funds except to the extent required by law. The Trustee
(acting in any capacity hereunder) shall be under no liability for interest on
any money received by it hereunder unless otherwise agreed in writing with the
Company.

               SECTION 7.02 Rights of Trustee. Subject to its duties and
responsibilities under the TIA,

                                       41
<PAGE>   48

               (a) The Trustee may rely on any document believed by it to be
genuine and to have been signed or presented by the proper person. The Trustee
need not investigate any fact or matter stated in the document.

               (b) Before the Trustee acts or refrains from acting, it may
require an Officers' Certificate or an Opinion of Counsel. The Trustee shall not
be liable for any action it takes or omits to take in good faith in reliance on
such Officers' Certificate or Opinion of Counsel.

               (c) The Trustee may act through agents and shall not be
responsible for the misconduct or negligence of any agent appointed with due
care.

               (d) Subject to the provisions of Section 7.01(c), the Trustee
shall not be liable for any action it takes or omits to take in good faith which
it believes to be authorized or within its rights or powers.

               (e) The Trustee may consult with counsel selected by it and any
advice or Opinion of Counsel shall be full and complete authorization and
protection in respect of any action taken or suffered or omitted by it hereunder
in good faith and in accordance with such advice or Opinion of Counsel.

               (f) The Trustee shall be under no obligation to exercise any of
the rights or powers vested in it by this Indenture at the request, order or
direction of any of the Holders, pursuant to the provisions of this Indenture,
unless such Holders shall have offered to the Trustee reasonable security or
indemnity against the costs, expenses and liabilities which may be incurred
therein or thereby.

               (g) The Trustee shall not be bound to verify or make any
investigation into the facts or matters stated in any resolution, certificate,
statement, opinion, report, notice, request or consent.

               SECTION 7.03 Individual Rights of Trustee. The Trustee in its
individual or any other capacity may become the owner or pledgee of Securities
and may otherwise deal with the Company or its Affiliates with the same rights
it would have if it were not Trustee. Any Paying Agent, Registrar, Conversion
Agent or co-registrar may do the same with like rights. However, the Trustee
must comply with Sections 7.10 and 7.11.

               SECTION 7.04 Trustee's Disclaimer. The Trustee makes no
representation as to the validity or adequacy of this Indenture or the
Securities, it shall not be accountable for the Company's use or application of
the proceeds from the Securities, it shall not be responsible for any statement
in the offering statement or the registration statement for the Securities under
the Securities Act or in the Indenture or the Securities (other than its
certificate of authentication), or the determination as to which beneficial
owners are entitled to receive any notices hereunder.

               SECTION 7.05 Notice of Defaults. If a Default occurs and if it is
known to the Trustee, the Trustee shall give to each Securityholder notice of
the Default within 90 days after it occurs unless such Default shall have been
cured or waived before the giving of such notice. Except in the case of a
Default described in Section 6.01(1) or (2), the Trustee may

                                       42
<PAGE>   49

withhold the notice if and so long as a committee of its Responsible Officers in
good faith determines that withholding the notice is in the interests of
Securityholders. The second sentence of this Section 7.05 shall be in lieu of
the proviso to Section 315(b) of the TIA and such proviso is hereby expressly
excluded from this Indenture, as permitted by the TIA. The Trustee shall not be
deemed to have knowledge of a Default unless a Responsible Officer of the
Trustee has received written notice of such Default.

               SECTION 7.06 Reports by Trustee to Holders. Within 60 days after
each May 1 beginning with the May 1 following the date of this Indenture, the
Trustee shall mail to each Securityholder a brief report dated as of such May 1
that complies with TIA Section 313(a), if required by such Section 313(a). The
Trustee also shall comply with TIA Section 313(b).

               A copy of each report at the time of its mailing to
Securityholders shall be filed with the SEC and each securities exchange, if
any, on which the Securities are listed. The Company agrees to notify the
Trustee whenever the Securities become listed on any securities exchange and of
any delisting thereof.

               SECTION 7.07 Compensation and Indemnity. The Company agrees:

               (a) to pay to the Trustee from time to time reasonable
               compensation for all services rendered by it hereunder (which
               compensation shall not be limited (to the extent permitted by
               law) by any provision of law in regard to the compensation of a
               trustee of an express trust);

               (b) to reimburse the Trustee upon its request for all reasonable
               expenses, disbursements and advances incurred or made by the
               Trustee in accordance with any provision of this Indenture
               (including the reasonable compensation and the expenses, advances
               and disbursements of its agents and counsel), except any such
               expense, disbursement or advance as may be attributable to its
               negligence or bad faith; and

               (c) to indemnify the Trustee for, and to hold it harmless
               against, any loss, damage, claim, liability, cost or expense
               (including attorney's fees) incurred without negligence or bad
               faith on its part, arising out of or in connection with the
               acceptance or administration of this trust, including the costs
               and expenses of enforcing this Indenture (including Section 7.07)
               against the Company, defending itself against any claim (whether
               asserted by any Holder or the Company) or liability in connection
               with the exercise or performance of any of its powers or duties
               hereunder.

               To secure the Company's payment obligations in this Section 7.07,
the Trustee shall have a lien prior to the Securities on all money or property
held or collected by the Trustee, except that held in trust to pay the Principal
Amount at Maturity, Issue Price plus accrued Original Issue Discount, Redemption
Price, Purchase Price, Change in Control Purchase Price or interest, if any, as
the case may be, on particular Securities.

               The Company's payment obligations pursuant to this Section 7.07
shall survive the discharge of this Indenture. When the Trustee incurs expenses
after the occurrence of a

                                       43
<PAGE>   50

Default specified in Section 6.01(5) or (6), the expenses are intended to
constitute expenses of administration under any Bankruptcy Law.

               SECTION 7.08 Replacement of Trustee. The Trustee may resign by so
notifying the Company; provided, however, no such resignation shall be effective
until a successor Trustee has accepted its appointment pursuant to this Section
7.08. The Holders of a majority in aggregate Principal Amount at Maturity of the
Securities at the time outstanding may remove the Trustee by so notifying the
Trustee and the Company. The Company shall remove the Trustee if:

               (1) the Trustee fails to comply with Section 7.10;

               (2) the Trustee is adjudged bankrupt or insolvent;

               (3) a receiver or public officer takes charge of the Trustee or
               its property; or

               (4) the Trustee otherwise becomes incapable of acting.

               If the Trustee resigns or is removed or if a vacancy exists in
the office of Trustee for any reason, the Company shall promptly appoint, by
resolution of its Board of Directors, a successor Trustee.

               A successor Trustee shall deliver a written acceptance of its
appointment to the retiring Trustee and to the Company satisfactory in form and
substance to the retiring Trustee and the Company. Thereupon the resignation or
removal of the retiring Trustee shall become effective, and the successor
Trustee shall have all the rights, powers and duties of the Trustee under this
Indenture. The successor Trustee shall mail a notice of its succession to
Securityholders. The retiring Trustee shall promptly transfer all property held
by it as Trustee to the successor Trustee, subject to the lien provided for in
Section 7.07.

               If a successor Trustee does not take office within 30 days after
the retiring Trustee resigns or is removed, the retiring Trustee, the Company or
the Holders of a majority in aggregate Principal Amount at Maturity of the
Securities at the time outstanding may petition any court of competent
jurisdiction for the appointment of a successor Trustee.

               If the Trustee fails to comply with Section 7.10, any
Securityholder may petition any court of competent jurisdiction for the removal
of the Trustee and the appointment of a successor Trustee.

               SECTION 7.09 Successor Trustee by Merger. If the Trustee
consolidates with, merges or converts into, or transfers all or substantially
all its corporate trust business or assets to, another corporation, the
resulting, surviving or transferee corporation without any further act shall be
the successor Trustee.

               SECTION 7.10 Eligibility; Disqualification. The Trustee shall at
all times satisfy the requirements of TIA Sections 310(a)(1) and 310(b). The
Trustee (or its parent holding company) shall have a combined capital and
surplus of at least $50,000,000 as set forth in its most recent published annual
report of condition. Nothing herein contained shall prevent the

                                       44
<PAGE>   51

Trustee from filing with the Commission the application referred to in the
penultimate paragraph of TIA Section 310(b).

               SECTION 7.11 Preferential Collection of Claims Against Company.
The Trustee shall comply with TIA Section 311(a), excluding any creditor
relationship listed in TIA Section 311(b). A Trustee who has resigned or been
removed shall be subject to TIA Section 311(a) to the extent indicated therein.

                                    ARTICLE 8

                             DISCHARGE OF INDENTURE

               SECTION 8.01 Discharge of Liability on Securities. When (i) the
Company delivers to the Trustee all outstanding Securities (other than
Securities replaced pursuant to Section 2.07) for cancellation or (ii) all
outstanding Securities have become due and payable and the Company deposits with
the Trustee cash or, if expressly permitted by the terms of the Securities,
Common Stock sufficient to pay all amounts due and owing on all outstanding
Securities (other than Securities replaced pursuant to Section 2.07), and if in
either case the Company pays all other sums payable hereunder by the Company,
then this Indenture shall, subject to Section 7.07, cease to be of further
effect. The Trustee shall join in the execution of a document prepared by the
Company acknowledging satisfaction and discharge of this Indenture on demand of
the Company accompanied by an Officers' Certificate and Opinion of Counsel and
at the cost and expense of the Company.

               SECTION 8.02 Repayment to the Company. The Trustee and the Paying
Agent shall return to the Company upon written request any money or securities
held by them for the payment of any amount with respect to the Securities that
remains unclaimed for two years, subject to applicable unclaimed property law.
After return to the Company, Holders entitled to the money or securities must
look to the Company for payment as general creditors unless an applicable
abandoned property law designates another person and the Trustee and the Paying
Agent shall have no further liability to the Securityholders with respect to
such money or securities for that period commencing after the return thereof.

                                    ARTICLE 9

                                   AMENDMENTS

               SECTION 9.01 Without Consent of Holders. The Company and the
Trustee may amend this Indenture or the Securities without the consent of any
Securityholder:

               (1) to cure any ambiguity, omission, defect or inconsistency;

               (2) to comply with Article 5 or Section 11.14;

               (3) to provide for uncertificated Securities in addition to
               certificated Securities so long as such uncertificated Securities
               are in registered form for purposes of the Internal Revenue Code
               of 1986, as amended;

                                       45
<PAGE>   52

               (4) to make any change that does not adversely affect the rights
               of any Securityholder; or

               (5) to make any change to comply with the TIA, or any amendment
               thereto, or to comply with any requirement of the SEC in
               connection with the qualification of the Indenture under the TIA.

               SECTION 9.02 With Consent of Holders. With the written consent of
the Holders of at least a majority in aggregate Principal Amount at Maturity of
the Securities at the time outstanding, the Company and the Trustee may amend
this Indenture or the Securities. However, without the consent of each
Securityholder affected, an amendment to this Indenture or the Securities may
not:

               (1) make any change to the Principal Amount at Maturity of
               Securities whose Holders must consent to an amendment;

               (2) make any change in the manner or rate of accrual in
               connection with Original Issue Discount, reduce the rate of
               interest referred to in paragraph 1 of the Securities, reduce the
               rate of interest referred to in Section 10.01 upon the occurrence
               of a Tax Event, or extend the time for payment of Original Issue
               Discount or interest, if any, on any Security;

               (3) reduce the Principal Amount at Maturity, Restated Principal
               Amount or the Issue Price of or extend the Stated Maturity of any
               Security;

               (4) reduce the Redemption Price, Purchase Price or Change in
               Control Purchase Price of any Security;

               (5) make any Security payable in money or securities other than
               that stated in the Security;

               (6) make any change in Section 6.04, Section 6.07 or this Section
               9.02, except to increase any percentage set forth therein;

               (7) make any change that adversely affects the right to convert
               any Security; or

               (8) make any change that adversely affects the right to require
               the Company to purchase the Securities in accordance with the
               terms thereof and this Indenture.

               It shall not be necessary for the consent of the Holders under
this Section 9.02 to approve the particular form of any proposed amendment, but
it shall be sufficient if such consent approves the substance thereof.

               After an amendment under this Section 9.02 becomes effective, the
Company shall mail to each Holder a notice briefly describing the amendment.

                                       46
<PAGE>   53

               SECTION 9.03 Compliance with Trust Indenture Act. Every
supplemental indenture executed pursuant to this Article shall comply with the
TIA.

               SECTION 9.04 Revocation and Effect of Consents, Waivers and
Actions. Until an amendment, waiver or other action by Holders becomes
effective, a consent thereto by a Holder of a Security hereunder is a continuing
consent by the Holder and every subsequent Holder of that Security or portion of
the Security that evidences the same obligation as the consenting Holder's
Security, even if notation of the consent, waiver or action is not made on the
Security. However, any such Holder or subsequent Holder may revoke the consent,
waiver or action as to such Holder's Security or portion of the Security if the
Trustee receives the notice of revocation before the date the amendment, waiver
or action becomes effective. After an amendment, waiver or action becomes
effective, it shall bind every Securityholder.

               SECTION 9.05 Notation on or Exchange of Securities. Securities
authenticated and delivered after the execution of any supplemental indenture
pursuant to this Article may, and shall if required by the Trustee, bear a
notation in form approved by the Trustee as to any matter provided for in such
supplemental indenture. If the Company shall so determine, new Securities so
modified as to conform, in the opinion of the Trustee and the Board of
Directors, to any such supplemental indenture may be prepared and executed by
the Company and authenticated and delivered by the Trustee in exchange for
outstanding Securities.

               SECTION 9.06 Trustee to Sign Supplemental Indentures. The Trustee
shall sign any supplemental indenture authorized pursuant to this Article 9 if
the amendment contained therein does not adversely affect the rights, duties,
liabilities or immunities of the Trustee. If it does, the Trustee may, but need
not, sign such supplemental indenture. In signing such supplemental indenture
the Trustee shall be entitled to receive, and (subject to the provisions of
Section 7.01) shall be fully protected in relying upon, an Officers' Certificate
and an Opinion of Counsel stating that such amendment is authorized or permitted
by this Indenture.

               SECTION 9.07 Effect of Supplemental Indentures. Upon the
execution of any supplemental indenture under this Article, this Indenture shall
be modified in accordance therewith, and such supplemental indenture shall form
a part of this Indenture for all purposes; and every Holder of Securities
theretofore or thereafter authenticated and delivered hereunder shall be bound
thereby.

                                   ARTICLE 10

                          SPECIAL TAX EVENT CONVERSION

               SECTION 10.01 Optional Conversion to Semiannual Coupon Note Upon
Tax Event. From and after (i) the date (the "Tax Event Date") of the occurrence
of a Tax Event and (ii) the date the Company exercises such option, whichever is
later (the "Option Exercise Date"), at the option of the Company, interest in
lieu of future Original Issue Discount shall accrue at the rate of 2.50% per
annum on a restated principal amount per $1,000 original Principal Amount at
Maturity (the "Restated Principal Amount") equal to the Issue Price plus
Original Issue Discount accrued through the Option Exercise Date and shall be
payable semiannually on November 1 and May 1 of each year (each an "Interest
Payment Date") to

                                       47
<PAGE>   54

holders of record at the close of business on October 15 or April 15 (each a
"Regular Record Date") immediately preceding such Interest Payment Date.
Interest will be computed on the basis of a 360-day year comprised of twelve
30-day months and will accrue from the most recent date on which interest has
been paid or, if no interest has been paid, from the Option Exercise Date.
Within 15 days of the occurrence of a Tax Event, the Company shall mail a
written notice of such Tax Event by first-class mail to the Trustee and within
15 days of its exercise of such option the Company shall mail a written notice
of the Option Exercise Date by first-class mail to the Trustee and Holders of
the Securities. From and after the Option Exercise Date, (i) the Company shall
be obligated to pay at Stated Maturity, in lieu of the Principal Amount at
Maturity of a Security, the Restated Principal Amount thereof and (ii) "Issue
Price and accrued Original Issue Discount," "Issue Price plus Original Issue
Discount" or similar words, as used herein, shall mean Restated Principal Amount
plus accrued and unpaid interest with respect to any Security. Securities
authenticated and delivered after the Option Exercise Date may, and shall if
required by the Trustee, bear a notation in a form approved by the Trustee as to
the conversion of the Securities to semiannual coupon notes.

               SECTION 10.02 Payment of Interest; Interest Rights Preserved. (a)
Interest on any Security that is payable, and is punctually paid or duly
provided for, on any Interest Payment Date shall be paid to the person in whose
name that Security is registered at the close of business on the Regular Record
Date for such interest at the office or agency of the Company maintained for
such purpose. Each installment of interest on any Security shall be paid in
same-day funds by transfer to an account maintained by the payee located inside
the United States. In the case of a permanent Global Security, interest payable
on any Interest Payment Date will be paid to the Depositary, with respect to
that portion of such permanent Global Security held for its account by Cede &
Co. for the purpose of permitting such party to credit the interest received by
it in respect of such permanent Global Security to the accounts of the
beneficial owners thereof.

               (b) Except as otherwise specified with respect to the Securities,
any interest on any Security that is payable, but is not punctually paid or duly
provided for, within 30 days following on any Interest Payment Date (herein
called "Defaulted Interest", which term shall include any accrued and unpaid
interest that has accrued on such defaulted amount in accordance with paragraph
1 of the Securities), shall forthwith cease to be payable to the registered
Holder thereof on the relevant Regular Record Date by virtue of having been such
Holder, and such Defaulted Interest may be paid by the Company, as its election
in each case, as provided in clause (1) or (2) below:

               (1) The Company may elect to make payment of any Defaulted
               Interest to the persons in whose names the Securities are
               registered at the close of business on a Special Record Date for
               the payment of such Defaulted Interest, which shall be fixed in
               the following manner. The Company shall notify the Trustee in
               writing of the amount of Defaulted Interest proposed to be paid
               on each Security and the date of the proposed payment (which
               shall not be less than 20 days after such notice is received by
               the Trustee), and at the same time the Company shall deposit with
               the Trustee an amount of money equal to the aggregate amount
               proposed to be paid in respect of such Defaulted Interest or
               shall make arrangements satisfactory to the Trustee for such
               deposit on or prior to the date of the proposed payment, such
               money when deposited to be held in trust for the benefit of the

                                       48
<PAGE>   55

               persons entitled to such Defaulted Interest as in this clause
               provided. Thereupon the Trustee shall fix a Special Record Date
               for the payment of such Defaulted Interest which shall be not
               more than 15 days and not less than 10 days prior to the date of
               the proposed payment and not less than 10 days after the receipt
               by the Trustee of the notice of the proposed payment. The Trustee
               shall promptly notify the Company of such Special Record Date
               and, in the name and at the expense of the Company, shall cause
               notice of the proposed payment of such Defaulted Interest and the
               Special Record Date therefor to be mailed, first-class postage
               prepaid, to each Holder of Securities at his address as it
               appears on the list of Securityholders maintained pursuant to
               Section 2.05 not less than 10 days prior to such Special Record
               Date. Notice of the proposed payment of such Defaulted Interest
               and the Special Record Date therefor having been mailed as
               aforesaid, such Defaulted Interest shall be paid to the persons
               in whose names the Securities are registered at the close of
               business on such Special Record Date and shall no longer be
               payable pursuant to the following clause (2).

               (2) The Company may make payment of any Defaulted Interest on the
               Securities in any other lawful manner not inconsistent with the
               requirements of any securities exchange on which such Securities
               may be listed, and upon such notice as may be required by such
               exchange, if, after notice given by the Company to the Trustee of
               the proposed payment pursuant to this clause, such manner of
               payment shall be deemed practicable by the Trustee.

               Subject to the foregoing provisions of this Section and Section
2.06, each Security delivered under this Indenture upon registration of transfer
of or in exchange for or in lieu of any other Security shall carry the rights to
interest accrued and unpaid, and to accrue, which were carried by such other
Security.

                                   ARTICLE 11

                                   CONVERSION

               SECTION 11.01 Conversion Privilege. A Holder of a Security may
convert such Security into Common Stock at any time during the period stated in
paragraph 8 of the Securities. The number of shares of Common Stock issuable
upon conversion of a Security per $1,000 of Principal Amount at Maturity thereof
(the "Conversion Rate") shall be that set forth in paragraph 8 in the
Securities, subject to adjustment as herein set forth.

               A Holder may convert a portion of the Principal Amount at
Maturity of a Security if the portion is $1,000 or an integral multiple of
$1,000. Provisions of this Indenture that apply to conversion of all of a
Security also apply to conversion of a portion of a Security.

               "Quoted Price" means, for any given day, the last reported per
share sale price (or, if no sale price is reported, the average of the bid and
ask prices or, if more than one in either case, the average of the average bid
and average ask prices) on such day of the Common Stock on the New York Stock
Exchange Composite Tape or, in the event shares of Common Stock are not listed
on the New York Stock Exchange, in the composite transactions for such other
national

                                       49
<PAGE>   56

or regional securities exchange upon which the Common Stock is listed, or, if
the shares of Common Stock are not listed on a national or regional securities
exchange, as quoted on the National Association of Securities Dealers Automated
Quotation System or by the National Quotation Bureau Incorporated. In the
absence of such quotations, the Company shall be entitled to determine the
Quoted Price on the basis of such quotations as it considers appropriate.

               "Average Quoted Price" means the average of the Quoted Prices of
the Common Stock for the shorter of

               (i) 30 consecutive trading days ending on the last full trading
               day prior to the Time of Determination with respect to the
               rights, warrants or options or distribution in respect of which
               the Average Quoted Price is being calculated, or

               (ii) the period (x) commencing on the date next succeeding the
               first public announcement of (a) the issuance of rights, warrants
               or options or (b) the distribution, in each case, in respect of
               which the Average Quoted Price is being calculated and (y)
               proceeding through the last full trading day prior to the Time of
               Determination with respect to the rights, warrants or options or
               distribution in respect of which the Average Quoted Price is
               being calculated (excluding days within such period, if any,
               which are not trading days), or

               (iii) the period, if any, (x) commencing on the date next
               succeeding the Ex-Dividend Time with respect to the next
               preceding (a) issuance of rights, warrants or options or (b)
               distribution, in each case, for which an adjustment is required
               by the provisions of Section 11.06(4), 11.07 or 11.08 and (y)
               proceeding through the last full trading day prior to the Time of
               Determination with respect to the rights, warrants or options or
               distribution in respect of which the Average Quoted Price is
               being calculated (excluding days within such period, if any,
               which are not trading days).

               In the event that the Ex-Dividend Time (or in the case of a
subdivision, combination or reclassification, the effective date with respect
thereto) with respect to a dividend, subdivision, combination or
reclassification to which Section 11.06(1), (2), (3) or (5) applies occurs
during the period applicable for calculating "Average Quoted Price" pursuant to
the definition in the preceding sentence, "Average Quoted Price" shall be
calculated for such period in a manner determined by the Board of Directors to
reflect the impact of such dividend, subdivision, combination or
reclassification on the Quoted Price of the Common Stock during such period.

               "Time of Determination" means the time and date of the earlier of
(i) the determination of stockholders entitled to receive rights, warrants or
options or a distribution, in each case, to which Section 11.07 or 11.08 applies
and (ii) the time ("Ex-Dividend Time") immediately prior to the commencement of
"ex-dividend" trading for such rights, warrants or options or distribution on
the New York Stock Exchange or such other national or regional exchange or
market on which the Common Stock is then listed or quoted.

                                       50
<PAGE>   57

               SECTION 11.02 Conversion Procedure. To convert a Security a
Holder must satisfy the requirements in paragraph 8 of the Securities. The date
on which the Holder satisfies all those requirements is the conversion date (the
"Conversion Date"). As soon as practicable after the Conversion Date, the
Company shall deliver to the Holder, through the Conversion Agent, a certificate
for the number of full shares of Common Stock issuable upon the conversion and
cash in lieu of any fractional share determined pursuant to Section 11.03. The
person in whose name the certificate is registered shall be treated as a
stockholder of record on and after the Conversion Date; provided, however, that
no surrender of a Security on any date when the stock transfer books of the
Company shall be closed shall be effective to constitute the person or persons
entitled to receive the shares of Common Stock upon such conversion as the
record holder or holders of such shares of Common Stock on such date, but such
surrender shall be effective to constitute the person or persons entitled to
receive such shares of Common Stock as the record holder or holders thereof for
all purposes at the close of business on the next succeeding day on which such
stock transfer books are open; such conversion shall be at the Conversion Rate
in effect on the date that such Security shall have been surrendered for
conversion, as if the stock transfer books of the Company had not been closed.
Upon conversion of a Security, such person shall no longer be a Holder of such
Security.

               No payment or adjustment will be made for dividends on, or other
distributions with respect to, any Common Stock except as provided in this
Article 11. On conversion of a Security, that portion of accrued Original Issue
Discount (or interest, if the Company has exercised its option provided for in
Section 10.01) attributable to the period from the Issue Date (or, if the
Company has exercised the option provided for in Section 10.01, the later of (x)
the date of such exercise and (y) the date on which interest was last paid) of
the Security through the Conversion Date with respect to the converted Security
shall not be cancelled, extinguished or forfeited, but rather shall be deemed to
be paid in full to the Holder thereof through delivery of the Common Stock
(together with the cash payment, if any, in lieu of fractional shares) in
exchange for the Security being converted pursuant to the provisions hereof; and
the fair market value of such shares of Common Stock (together with any such
cash payment in lieu of fractional shares) shall be treated as issued, to the
extent thereof, first in exchange for Original Issue Discount (or interest, if
the Company has exercised its option provided for in Section 10.01) accrued
through the Conversion Date, and the balance, if any, of such fair market value
of such Common Stock (and any such cash payment) shall be treated as issued in
exchange for the Issue Price of the Security being converted pursuant to the
provisions hereof.

               If the Holder converts more than one Security at the same time,
the number of shares of Common Stock issuable upon the conversion shall be based
on the total Principal Amount at Maturity of the Securities converted.

               If the last day on which a Security may be converted is a Legal
Holiday, the Security may be surrendered on the next succeeding day that is not
a Legal Holiday.

               Upon surrender of a Security that is converted in part, the
Company shall execute, and the Trustee shall authenticate and the Registrar
shall deliver to the Holder, a new Security in an authorized denomination equal
in Principal Amount at Maturity to the unconverted portion of the Security
surrendered.

                                       51
<PAGE>   58

               SECTION 11.03 Fractional Shares. The Company will not issue a
fractional share of Common Stock upon conversion of a Security. Instead, the
Company will deliver cash for the current market value of the fractional share.
The current market value of a fractional share shall be determined, to the
nearest 1/1,000th of a share, by multiplying the Quoted Price, on the last
trading day prior to the Conversion Date, of a full share by the fractional
amount and rounding the product to the nearest whole cent.

               SECTION 11.04 Taxes on Conversion. If a Holder converts a
Security, the Company shall pay any documentary, stamp or similar issue or
transfer tax due on the issue of shares of Common Stock upon the conversion.
However, the Holder shall pay any such tax which is due because the Holder
requests the shares to be issued in a name other than the Holder's name. The
Conversion Agent may refuse to deliver the certificates representing the Common
Stock being issued in a name other than the Holder's name until the Conversion
Agent receives a sum sufficient to pay any tax which will be due because the
shares are to be issued in a name other than the Holder's name. Nothing herein
shall preclude any tax withholding required by law or regulations.

               SECTION 11.05 Company to Provide Stock. The Company shall, prior
to issuance of any Securities under this Article 11, and from time to time as
may be necessary, reserve out of its authorized but unissued Common Stock a
sufficient number of shares of Common Stock to permit the conversion of the
Securities.

               All shares of Common Stock delivered upon conversion of the
Securities shall be newly issued shares or treasury shares, shall be duly and
validly issued and fully paid and nonassessable and shall be free from
preemptive rights and free of any lien or adverse claim.

               The Company will endeavor promptly to comply with all Federal and
state securities laws regulating the offer and delivery of shares of Common
Stock upon conversion of Securities, if any, and will list or cause to have
quoted such shares of Common Stock on each national securities exchange or in
the over-the-counter market or such other market on which the Common Stock is
then listed or quoted.

               SECTION 11.06 Adjustment for Change In Capital Stock. If, after
the Issue Date of the Securities, the Company:

               (1) pays a dividend or makes a distribution on its Common Stock
               in shares of its Common Stock;

               (2) subdivides its outstanding shares of Common Stock into a
               greater number of shares;

               (3) combines its outstanding shares of Common Stock into a
               smaller number of shares;

               (4) pays a dividend or makes a distribution on its Common Stock
               in shares of its Capital Stock (other than Common Stock or
               rights, warrants or options for its Capital Stock); or

                                       52
<PAGE>   59

               (5) issues by reclassification of its Common Stock any shares of
               its Capital Stock (other than rights, warrants or options for its
               Capital Stock), then the conversion privilege and the Conversion
               Rate in effect immediately prior to such action shall be adjusted
               so that the Holder of a Security thereafter converted may receive
               the number of shares of Capital Stock of the Company which such
               Holder would have owned immediately following such action if such
               Holder had converted the Security immediately prior to such
               action.

               The adjustment shall become effective immediately after the
record date in the case of a dividend or distribution and immediately after the
effective date in the case of a subdivision, combination or reclassification.

               If after an adjustment a Holder of a Security upon conversion of
such Security may receive shares of two or more classes of Capital Stock of the
Company, the Conversion Rate shall thereafter be subject to adjustment upon the
occurrence of an action taken with respect to any such class of Capital Stock as
is contemplated by this Article 11 with respect to the Common Stock, on terms
comparable to those applicable to Common Stock in this Article 11.

               SECTION 11.07 Adjustment for Rights Issue. If after the Issue
Date of the Securities, the Company distributes any rights, warrants or options
to all holders of its Common Stock entitling them, for a period expiring within
60 days after the record date for such distribution, to purchase shares of
Common Stock at a price per share less than the Quoted Price as of the Time of
Determination, the Conversion Rate shall be adjusted in accordance with the
formula:

<TABLE>
<CAPTION>

                             <S>    <C>     <C>
                             R'  =  R  x         (O + N)
                                            -------------------
                                             (O + (N x P)/M)
</TABLE>

        where:

        R' = the adjusted Conversion Rate.

        R = the current Conversion Rate.

        O = the number of shares of Common Stock outstanding on the record date
for the distribution to which this Section 11.07 is being applied.

        N = the number of additional shares of Common Stock offered pursuant to
the distribution.

        P = the offering price per share of the additional shares.

        M = the Average Quoted Price, minus, in the case of (i) a distribution
to which Section 11.06(4) applies or (ii) a distribution to which Section 11.08
applies, for which, in each case, (x) the record date shall occur on or before
the record date for the distribution to which this Section 11.07 applies and (y)
the Ex-Dividend Time shall occur on or after the date of the Time of

                                       53
<PAGE>   60

Determination for the distribution to which this Section 11.07 applies, the fair
market value (on the record date for the distribution to which this Section
11.07 applies) of the

               (1) Capital Stock of the Company distributed in respect of each
               share of Common Stock in such Section 11.06(4) distribution and

               (2) assets of the Company or debt securities or any rights,
               warrants or options to purchase securities of the Company
               distributed in respect of each share of Common Stock in such
               Section 11.08 distribution.

        The Board of Directors shall determine fair market values for the
purposes of this Section 11.07.

               The adjustment shall become effective immediately after the
record date for the determination of shareholders entitled to receive the
rights, warrants or options to which this

               Section 11.07 applies. If all of the shares of Common Stock
subject to such rights, warrants or options have not been issued when such
rights, warrants or options expire, then the Conversion Rate shall promptly be
readjusted to the Conversion Rate which would then be in effect had the
adjustment upon the issuance of such rights, warrants or options been made on
the basis of the actual number of shares of Common Stock issued upon the
exercise of such rights, warrants or options.

               No adjustment shall be made under this Section 11.07 if the
application of the formula stated above in this Section 11.07 would result in a
value of R' that is equal to or less than the value of R.

               SECTION 11.08 Adjustment for Other Distributions. If, after the
Issue Date of the Securities, the Company distributes to all holders of its
Common Stock any of its assets, or debt securities or any rights, warrants or
options to purchase securities of the Company (including securities or cash, but
excluding (x) distributions of Capital Stock referred to in Section 11.06 and
distributions of rights, warrants or options referred to in Section 11.07 and
(y) cash dividends or other cash distributions that are paid out of consolidated
current net earnings or earnings retained in the business as shown on the books
of the Company unless such cash dividends or other cash distributions are
Extraordinary Cash Dividends) the Conversion Rate shall be adjusted, subject to
the provisions of the last paragraph of this Section 11.08, in accordance with
the formula:

<TABLE>
<CAPTION>

                                    <S>    <C> <C>
                                    R'  =  R x   M
                                               -----
                                                M-F
</TABLE>

where:

        R' = the adjusted Conversion Rate.

        R = the current Conversion Rate.

        M = the Average Quoted Price, minus, in the case of a distribution to
which Section 11.06(4) applies, for

                                       54
<PAGE>   61

        which (i) the record date shall occur on or before the record date for
        the distribution to which this Section 11.08 applies and (ii) the
        Ex-Dividend Time shall occur on or after the date of the Time of
        Determination for the distribution to which this Section 11.08 applies,
        the fair market value (on the record date for the distribution to which
        this Section 11.08 applies) of any Capital Stock of the Company
        distributed in respect of each share of Common Stock in such Section
        11.06(4) distribution.

        F = the fair market value (on the record date for the distribution to
which this Section 11.08 applies) of the assets, securities, rights, warrants or
options to be distributed in respect of each share of Common Stock in the
distribution to which this Section 11.08 is being applied (including, in the
case of cash dividends or other cash distributions giving rise to an adjustment,
all such cash distributed concurrently).

        The Board of Directors shall determine fair market values for the
        purposes of this Section 11.08.

               The adjustment shall become effective immediately after the
record date for the determination of shareholders entitled to receive the
distribution to which this Section 11.08 applies.

               For purposes of this Section 11.08, the term "Extraordinary Cash
Dividend" shall mean any cash dividend with respect to the Common Stock the
amount of which, together with the aggregate amount of cash dividends on the
Common Stock to be aggregated with such cash dividend in accordance with the
provisions of this paragraph, equals or exceeds the threshold percentages set
forth in item (i) or (ii) below:

               (i) If, upon the date prior to the Ex-Dividend Time with respect
               to a cash dividend on the Common Stock, the aggregate amount of
               such cash dividend together with the amounts of all cash
               dividends on the Common Stock with Ex-Dividend Times occurring in
               the 85 consecutive day period ending on the date prior to the
               Ex-Dividend Time with respect to the cash dividend to which this
               provision is being applied equals or exceeds on a per share basis
               12.5% of the average of the Quoted Prices during the period
               beginning on the date after the first such Ex-Dividend Time in
               such period and ending on the date prior to the Ex-Dividend Time
               with respect to the cash dividend to which this provision is
               being applied (except that if no other cash dividend has had an
               Ex-Dividend Time occurring in such period, the period for
               calculating the average of the Quoted Prices shall be the period
               commencing 85 days prior to the date prior to the Ex-Dividend
               Time with respect to the cash dividend to which this provision is
               being applied), such cash dividend together with each other cash
               dividend with an Ex-Dividend Time occurring in such 85 day period
               shall be deemed to be an Extraordinary Cash Dividend and for
               purposes of applying the formula set forth above in this Section
               11.08, the value of "F" shall be equal to (w) the aggregate
               amount of such cash dividend together with the amounts of the
               other cash dividends with Ex-Dividend Times occurring in such
               period minus (x) the aggregate amount of such other cash
               dividends with Ex-Dividend Times

                                       55
<PAGE>   62

               occurring in such period for which a prior adjustment in the
               Conversion Rate was previously made under this Section 11.08.

               (ii) If, upon the date prior to the Ex-Dividend Time with respect
               to a cash dividend on the Common Stock, the aggregate amount of
               such cash dividend together with the amounts of all cash
               dividends on the Common Stock with Ex-Dividend Times occurring in
               the 365 consecutive day period ending on the date prior to the
               Ex-Dividend Time with respect to the cash dividend to which this
               provision is being applied equals or exceeds on a per share basis
               25% of the average of the Quoted Prices during the period
               beginning on the date after the first such Ex-Dividend Time in
               such period and ending on the date prior to the Ex-Dividend Time
               with respect to the cash dividend to which this provision is
               being applied (except that if no other cash dividend has had an
               Ex-Dividend Time occurring in such period, the period for
               calculating the average of the Quoted Prices shall be the period
               commencing 365 days prior to the date prior to the Ex-Dividend
               Time with respect to the cash dividend to which this provision is
               being applied), such cash dividend together with each other cash
               dividend with an Ex-Dividend Time occurring in such 365 day
               period shall be deemed to be an Extraordinary Cash Dividend and
               for purposes of applying the formula set forth above in this
               Section 11.08, the value of "F" shall be equal to (y) the
               aggregate amount of such cash dividend together with the amounts
               of the other cash dividends with Ex-Dividend Times occurring in
               such period minus (z) the aggregate amount of such other cash
               dividends with Ex-Dividend Times occurring in such period for
               which a prior adjustment in the Conversion Rate was previously
               made under this Section 11.08.

               In making the determinations required by items (i) and (ii)
               above, the amount of cash dividends paid on a per share basis and
               the average of the Quoted Prices, in each case during the period
               specified in item (i) or (ii) above, as applicable, shall be
               appropriately adjusted to reflect the occurrence during such
               period of any event described in Section 11.06.

               In the event that, with respect to any distribution to which this
Section 11.08 would otherwise apply, the difference "M-F" as defined in the
above formula is less than $1.00 or "F" is equal to or greater than "M", then
the adjustment provided by this Section 11.08 shall not be made and in lieu
thereof the provisions of Section 11.14 shall apply to such distribution.

               SECTION 11.09 When Adjustment May Be Deferred. No adjustment in
the Conversion Rate need be made unless the adjustment would require an increase
or decrease of at least 1% in the Conversion Rate. Any adjustments that are not
made shall be carried forward and taken into account in any subsequent
adjustment.

               All calculations under this Article 11 shall be made to the
nearest cent or to the nearest 1/1,000th of a share, as the case may be.

               SECTION 11.10 When No Adjustment Required. No adjustment need be
made for a transaction referred to in Section 11.06, 11.07, 11.08 or 11.14 if
Securityholders are

                                       56
<PAGE>   63

to participate in the transaction on a basis and with notice that the Board of
Directors determines to be fair and appropriate in light of the basis and notice
on which holders of Common Stock participate in the transaction. Such
participation by Securityholders may include participation upon conversion
provided that an adjustment shall be made at such time as the Securityholders
are no longer entitled to participate.

               No adjustment need be made for rights to purchase Common Stock
pursuant to a Company plan for reinvestment of dividends or interest.

               No adjustment need be made for a change in the par value or no
par value of the Common Stock.

               To the extent the Securities become convertible pursuant to this
Article 11 into cash, no adjustment need be made thereafter as to the cash.
Interest will not accrue on the cash.

               SECTION 11.11 Notice of Adjustment. Whenever the Conversion Rate
is adjusted, the Company shall promptly mail to Securityholders a notice of the
adjustment. The Company shall file with the Trustee and the Conversion Agent
such notice and a certificate from the Company's independent public accountants
briefly stating the facts requiring the adjustment and the manner of computing
it. The certificate shall be conclusive evidence that the adjustment is correct.
Neither the Trustee nor any Conversion Agent shall be under any duty or
responsibility with respect to any such certificate except to exhibit the same
to any Holder desiring inspection thereof.

               SECTION 11.12 Voluntary Increase. The Company from time to time
may increase the Conversion Rate by any amount for any period of time. Whenever
the Conversion Rate is increased, the Company shall mail to Securityholders and
file with the Trustee and the Conversion Agent a notice of the increase. The
Company shall mail the notice at least 15 days before the date the increased
Conversion Rate takes effect. The notice shall state the increased Conversion
Rate and the period it will be in effect.

               A voluntary increase of the Conversion Rate does not change or
adjust the Conversion Rate otherwise in effect for purposes of Section 11.06,
11.07 or 11.08.

SECTION 11.13  Notice of Certain Transactions.  If:

               (1) the Company takes any action that would require an adjustment
               in the Conversion Rate pursuant to Section 11.06, 11.07 or 11.08
               (unless no adjustment is to occur pursuant to Section 11.10); or

               (2) the Company takes any action that would require a
               supplemental indenture pursuant to Section 11.14; or

               (3) there is a liquidation or dissolution of the Company;

then the Company shall mail to Securityholders and file with the Trustee and the
Conversion Agent a notice stating the proposed record date for a dividend or
distribution or the proposed effective date of a subdivision, combination,
reclassification, consolidation, merger, binding

                                       57
<PAGE>   64

share exchange, transfer, liquidation or dissolution. The Company shall file and
mail the notice at least 15 days before such date. Failure to file or mail the
notice or any defect in it shall not affect the validity of the transaction.

               SECTION 11.14 Reorganization of Company; Special Distributions.
If the Company is a party to a transaction subject to Section 5.01 (other than a
sale of all or substantially all of the assets of the Company in a transaction
in which the holders of Common Stock immediately prior to such transaction do
not receive securities, cash or other assets of the Company or any other person)
or a merger or binding share exchange which reclassifies or changes its
outstanding Common Stock, the person obligated to deliver securities, cash or
other assets upon conversion of Securities shall enter into a supplemental
indenture. If the issuer of securities deliverable upon conversion of Securities
is an Affiliate of the successor Company, that issuer shall join in the
supplemental indenture.

               The supplemental indenture shall provide that the Holder of a
Security may convert it into the kind and amount of securities, cash or other
assets which such Holder would have received immediately after the
consolidation, merger, binding share exchange or transfer if such Holder had
converted the Security immediately before the effective date of the transaction,
assuming (to the extent applicable) that such Holder (i) was not a constituent
person or an Affiliate of a constituent person to such transaction; (ii) made no
election with respect thereto; and (iii) was treated alike with the plurality of
non-electing Holders. The supplemental indenture shall provide for adjustments
which shall be as nearly equivalent as may be practical to the adjustments
provided for in this Article 11. The successor Company shall mail to
Securityholders a notice briefly describing the supplemental indenture.

               If this Section applies, neither Section 11.06 nor 11.07 applies.

               If the Company makes a distribution to all holders of its Common
Stock of any of its assets, or debt securities or any rights, warrants or
options to purchase securities of the Company that, but for the provisions of
the last paragraph of Section 11.08, would otherwise result in an adjustment in
the Conversion Rate pursuant to the provisions of Section 11.08, then, from and
after the record date for determining the holders of Common Stock entitled to
receive the distribution, a Holder of a Security that converts such Security in
accordance with the provisions of this Indenture shall upon such conversion be
entitled to receive, in addition to the shares of Common Stock into which the
Security is convertible, the kind and amount of securities, cash or other assets
comprising the distribution that such Holder would have received if such Holder
had converted the Security immediately prior to the record date for determining
the holders of Common Stock entitled to receive the distribution.

               SECTION 11.15 Company Determination Final. Any determination that
the Company or the Board of Directors must make pursuant to Section 11.03,
11.06, 11.07, 11.08, 11.09, 11.10, 11.14 or 11.17 is conclusive.

               SECTION 11.16 Trustee's Adjustment Disclaimer. The Trustee has no
duty to determine when an adjustment under this Article 11 should be made, how
it should be made or what it should be. The Trustee has no duty to determine
whether a supplemental indenture under Section 11.14 need be entered into or
whether any provisions of any supplemental indenture are

                                       58
<PAGE>   65

correct. The Trustee shall not be accountable for and makes no representation as
to the validity or value of any securities or assets issued upon conversion of
Securities. The Trustee shall not be responsible for the Company's failure to
comply with this Article 11. Each Conversion Agent shall have the same
protection under this Section 11.16 as the Trustee.

               SECTION 11.17 Simultaneous Adjustments. In the event that this
Article 11 requires adjustments to the Conversion Rate under more than one of
Sections 11.06(4), 11.07 or 11.08, and the record dates for the distributions
giving rise to such adjustments shall occur on the same date, then such
adjustments shall be made by applying, first, the provisions of Section 11.06,
second, the provisions of Section 11.08 and, third, the provisions of Section
11.07.

               SECTION 11.18 Successive Adjustments. After an adjustment to the
Conversion Rate under this Article 11, any subsequent event requiring an
adjustment under this Article 11 shall cause an adjustment to the Conversion
Rate as so adjusted.

               SECTION 11.19 Rights Issued in Respect of Common Stock Issued
Upon Conversion. Each share of Common Stock issued upon conversion of Securities
pursuant to this Article 11 shall be entitled to receive the appropriate number
of common stock or preferred stock purchase rights, as the case may be (the
"Rights"), if any, and the certificates representing the Common Stock issued
upon such conversion shall bear such legends, if any, in each case as may be
provided by the terms of any shareholder rights agreement adopted by the
Company, as the same may be amended from time to time (in each case, a "Rights
Agreement"). Provided that such Rights Agreement requires that each share of
Common Stock issued upon conversion of Securities at any time prior to the
distribution of separate certificates representing the Rights be entitled to
receive such Rights, then, notwithstanding anything else to the contrary in this
Article 11, there shall not be any adjustment to the conversion privilege or
Conversion Rate as a result of the issuance of Rights, the distribution of
separate certificates representing the Rights, the exercise or redemption of
such Rights in accordance with any such Rights Agreement, or the termination or
invalidation of such Rights.

                                   ARTICLE 12

                                  SUBORDINATION

               SECTION 12.01 Securities Subordinate to Senior Indebtedness. The
Company covenants and agrees, and each Holder of a Security, by his acceptance
thereof, likewise covenants and agrees, that, to the extent and in the manner
hereinafter set forth in this Article 12, the indebtedness represented by the
Securities and the payment of the Principal Amount at Maturity, Issue Price,
accrued Original Issue Discount, Redemption Price, cash in respect of Purchase
Price, cash in respect of a conversion, Change in Control Purchase Price and
interest, if any, in respect of each and all of the Securities are hereby
expressly made subordinate and subject in right of payment to the prior payment
in full of all Senior Indebtedness of the Company, as the case may be.

               SECTION 12.02 Payment over of Proceeds upon Dissolution, Etc.
Upon any distribution of assets of the Company in the event of:

                                       59
<PAGE>   66

               (a) any insolvency or bankruptcy case or proceeding, or any
        receivership, liquidation, reorganization or other similar case or
        proceeding in connection therewith, relative to the Company or to its
        respective creditors, as such, or to its respective assets, or

               (b) any liquidation, dissolution or other winding-up of the
        Company, whether voluntary or involuntary and whether or not involving
        insolvency or bankruptcy, or

               (c) any assignment for the benefit of creditors or any other
        marshaling of assets and liabilities of the Company, or

               (d) any other event that would constitute an Event of Default
        specified in Section 6.01(5) or 6.01(6),

then, and in any such event, the holders of Senior Indebtedness shall be
entitled to receive:

               (1) payment in full in cash of all amounts due or to become due
        on or in respect of all Senior Indebtedness in cash or cash equivalents,
        or provision shall be made for such payment, before the Holders of the
        Securities are entitled to receive any payment on account of the
        Principal Amount at Maturity, Issue Price, accrued Original Issue
        Discount, Redemption Price, cash in respect of the Purchase Price, cash
        in respect of a conversion, Change of Control Purchase Price or
        interest, if any, in respect of the Securities, and

               (2) any payment or distribution of any kind or character, whether
        in cash, property or securities, which may be payable or deliverable in
        respect of the Securities in any such case, proceeding, dissolution,
        liquidation or other winding up or event, including any such payment or
        distribution which may be payable or deliverable by reason of the
        payment of any other indebtedness of the Company being subordinated to
        the payment of the Securities.

               In the event that, notwithstanding the foregoing provisions of
this Section, the Trustee or the Holder of any Security shall have received any
payment or distribution of assets of the Company of any kind or character,
whether in cash, property or securities, including any such payment or
distribution which may be payable or deliverable by reason of the payment of any
other indebtedness of the Company being subordinated to the payment of the
Securities, before all Senior Indebtedness is paid in full in cash or payment
thereof provided for, and if such fact shall, at or prior to the time of such
payment or distribution, have been made known to the Trustee or, as the case may
be, such Holder, then, in such event, such payment or distribution shall be paid
over or delivered forthwith to the trustee in bankruptcy, receiver, liquidating
trustee, Custodian, assignee, agent or other person making payment or
distribution of assets of the Company for application to the payment of all
Senior Indebtedness remaining unpaid, to the extent necessary to pay all Senior
Indebtedness in full in cash or as payment thereof is otherwise provided for (as
such phrase is defined below), after giving effect to any concurrent payment or
distribution to or for the holders of Senior Indebtedness.

               For purposes of this Article 12 only, the words "cash, property
or securities" shall not be deemed to include shares of Capital Stock of the
Company, as reorganized or readjusted,

                                       60
<PAGE>   67

or securities of the Company or any other corporation provided for by a plan or
reorganization or readjustment the payment of which is subordinated, at least to
the extent provided in this Article 12 with respect to the Securities, to the
payment of all Senior Indebtedness which may at the time be outstanding;
provided, however, that (i) Senior Indebtedness is assumed by the new
corporation, if any, resulting from any such reorganization or readjustment, and
(ii) the rights of the holders of the Senior Indebtedness are not, without the
consent of such holders, altered by such reorganization or readjustment.

               The consolidation of the Company with, or the merger of the
Company into, another person or the liquidation or dissolution of the Company
following the conveyance or transfer of its properties and assets substantially
as an entirety to another person upon the terms and conditions set forth in
Article 5 shall not be deemed a dissolution, winding up, liquidation,
reorganization, assignment for the benefit of creditors or marshalling of assets
and liabilities of the Company for the purposes of this Section if the person
formed by such consolidation or into which the Company is merged or the person
which acquires by conveyance or transfer such properties and assets of the
Company, as the case may be, substantially as an entirety, as the case may be,
shall as part of such consolidation, merger, conveyance or transfer, comply with
the conditions set forth in Article 5.

               SECTION 12.03 Acceleration of Securities. In the event that any
Securities are declared due and payable before their Stated Maturity pursuant to
Section 6.02, then and in such event the Company shall promptly notify holders
of Senior Indebtedness of such acceleration. The Company may not pay the
Securities until the earlier of (i) 120 or more days have passed after such
acceleration occurs or (ii) the payment in full of all Senior Indebtedness or as
payment thereof is otherwise provided for (as such phrase is defined below), and
may thereafter pay the Securities if this Indenture permits the payment at that
time.

               In the event that, notwithstanding the foregoing, (a) the Company
shall make any payment to the Trustee or the Holder of any Securities prohibited
by the foregoing provisions of this Section 12.03, and (b) with respect to any
payment made before 120 or more days have passed after such acceleration occurs
if such facts shall, at or prior to the time of such payment, have been made
known to the Trustee or, as the case may be, such Holder, then and in such event
such payment shall be paid over and delivered forthwith to the Company by or on
behalf of the person holding such payment for the benefit of the holders of
Senior Indebtedness.

               The provisions of this Section 12.03 shall not apply to any
payment with respect to which Section 12.02 would be applicable.

               SECTION 12.04 Default on Senior Indebtedness. The Company may not
make any payment of the Principal Amount at Maturity, Issue Price, accrued
Original Issue Discount, Redemption Price, Change of Control Purchase Price or
interest, if any, in respect of the Securities and may not pay cash with respect
to the Purchase Price (or portion thereof) or cash in respect of a conversion of
any Security or otherwise acquire any Securities for cash or property if:

               (1) any payment default on any Senior Indebtedness has occurred
        and is continuing beyond any applicable grace period with respect
        thereto; or

                                       61
<PAGE>   68

               (2) a default (other than a default referred to in the preceding
        clause (1)) on any Senior Indebtedness occurs and is continuing that
        permits holders of such Senior Indebtedness to accelerate the maturity
        thereof and the default is the subject of judicial proceedings or the
        Company receives a notice of default thereof from any person who may
        give such notice pursuant to the instrument evidencing or document
        governing such Senior Indebtedness.

If the Company receives any such notice, then a similar notice received within
nine months thereafter relating to the same default on the same issue of Senior
Indebtedness shall not be effective for purposes of this Section 12.04.

               The Company may resume payment on the Securities and may acquire
Securities if and when:

               (a) the default referred to above is cured or waived as provided
        or permitted in accordance with the terms of the applicable Senior
        Indebtedness; or

               (b) in the case of a default referred to in clause (2) of the
        preceding paragraph, 179 or more days pass after the receipt by the
        Company of the notice described in clause (2) above; and

this Indenture otherwise permits the payment or acquisition at that time;
provided, however, that with respect to payments made after the 179-day period
referred to in clause (b) of this Section 12.04, the Trustee or the Holder of
any Securities shall pay over and deliver forthwith to the Company for the
benefit of the holders of Senior Indebtedness any amounts received by the
Trustee or any such Holder to the extent necessary to pay all holders of Senior
Indebtedness in full in cash or otherwise provide for such payment thereof (as
such phrase is defined above).

               In the event that, notwithstanding the foregoing, (a) the Company
shall make any payment to the Trustee or the Holder of any Security prohibited
by the foregoing provisions of this Section, and (b) with respect to any payment
made after the expiration of the 179-day period if such fact shall then have
been made known to the Trustee or, as the case may be, such Holder, then and in
such event such payment shall (to the extent permitted by law) be paid over and
delivered forthwith to the Company by or on behalf of the person holding such
payment for the benefit of the holders of the Senior Indebtedness.

               The provisions of this Section shall not apply to any payment
with respect to which Section 12.02 would be applicable.

               SECTION 12.05 Payment Permitted If No Default. Nothing contained
in this Article 12 or elsewhere in this Indenture or in any of the Securities
shall prevent (a) the Company at any time except during the pendency of any
case, proceeding, dissolution, liquidation or other winding up, assignment for
the benefit of creditors or other marshaling of assets and liabilities of the
Company referred to in Section 12.02 or under the conditions described in
Section 12.03 or 12.04, from making payments at any time of Principal Amount at
Maturity, Issue Price, accrued Original Issue Discount, Redemption Price,
Purchase Price, Change of Control Purchase Price or interest, if any, as the
case may be, in respect of the Securities if the Trustee did not, at the time of
such application, have actual knowledge that such

                                       62
<PAGE>   69

payment would have been prohibited by the provisions of this Article 12 or (b)
the application by the Trustee of any money deposited with it hereunder to
payment of or on account of the Principal Amount at Maturity, Issue Price,
accrued Original Issue Discount, Redemption Price, Purchase Price, Change in
Control Purchase Price or interest, if any, as the case may be, in respect of
the Securities or the retention of such payment by the Holders of the
Securities, if, at the time of such application by the Trustee, the Trustee did
not have actual knowledge that such payment would have been prohibited by the
provisions of this Article 12.

               SECTION 12.06 Subrogation to Rights of Holders of Senior
Indebtedness. Subject to payment in full of all Senior Indebtedness to the
extent and in the manner set forth in this Article 12, the Holders of the
Securities shall be subrogated to the extent of the payments or distributions
made to the holders of such Senior Indebtedness pursuant to the provisions of
this Article 12 (equally and ratably with the holders of all indebtedness of the
Company which by its express terms is subordinated to indebtedness of the
Company to substantially the same extent as the Securities are subordinated and
is entitled to like rights of subrogation) to the rights of the holders of such
Senior Indebtedness to receive payments or distributions of cash, property and
securities applicable to the Senior Indebtedness until the Principal Amount at
Maturity, Issue Price, accrued Original Issue Discount, Redemption Price,
Purchase Price, Change of Control Purchase Price or interest, if any, as the
case may be, in respect of the Securities shall be paid in full. For purposes of
such subrogation, no payments or distributions to the holders of the Senior
Indebtedness of any cash, property or securities to which the Holders of the
Securities or the Trustee would be entitled except for the provisions of this
Article 12, and no payments over pursuant to the provisions of this Article 12
to the holders of Senior Indebtedness by Holders of the Securities or the
Trustee, shall, as among the Company, the creditors of the Company, other than
holders of Senior Indebtedness and the Holders of the Securities, be deemed to
be a payment or distribution by the Company to or on account of the Senior
Indebtedness.

               SECTION 12.07 Provisions Solely to Define Relative Rights. The
provisions of this Article 12 are and are intended solely for the purpose of
defining the relative rights of the Holders of the Securities, on the one hand,
and the holders of Senior Indebtedness, on the other hand. Nothing contained in
this Article 12 or elsewhere in this Indenture or in the Securities is intended
to or shall (a) impair, as among the Company, the creditors of the Company other
than holders of Senior Indebtedness and the Holders of the Securities, the
obligation of the Company, which is absolute and unconditional, to pay to the
Holders of the Securities the Principal Amount at Maturity, Issue Price, accrued
Original Issue Discount, Redemption Price, Purchase Price, Change of Control
Purchase Price or interest, if any, as the case may be, in respect of the
Securities as and when the same shall become due and payable in accordance with
the terms of the Securities and this Indenture; or (b) affect the relative
rights against the Company of the Holders of the Securities and creditors of the
Company other than the holders of Senior Indebtedness; or (c) prevent the
Trustee or the Holder of any Security from exercising all remedies otherwise
permitted by applicable law upon default under this Indenture, subject to the
rights, if any, under this Article 12 of the holders of Senior Indebtedness to
receive cash, property and securities otherwise payable or deliverable to the
Trustee or such Holder.

               SECTION 12.08 Trustee to Effectuate Subordination. Each Holder of
a Security by his acceptance thereof authorizes and directs the Trustee on his
behalf to take such

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<PAGE>   70

action as may be necessary or appropriate to effectuate the subordination
provided in this Article 12 and appoints the Trustee his attorney-in-fact for
any and all such purposes.

               SECTION 12.09 No Waiver of Subordination Provisions. No right of
any present or future holder of any Senior Indebtedness to enforce subordination
as herein provided shall at any time in any way be prejudiced or impaired by any
act or failure to act on the part of the Company or by any act or failure to act
by any such holder, or by any non-compliance by the Company with the terms,
provisions and covenants of this Indenture, regardless of any knowledge thereof
any such holder may have or be otherwise charged with.

               Without in any way limiting the generality of the foregoing
paragraph, the holders of Senior Indebtedness may, at any time and from time to
time, without the consent of or notice to the Trustee or the Holders of the
Securities, without incurring responsibility to the Holders of the Securities
and without impairing or releasing the subordination provided in this Article 12
or the obligations hereunder of the Holders of the Securities to the holders of
Senior Indebtedness, do any one or more of the following: (i) change the manner,
place or terms of payment or extend the time of payment of, or renew, increase
or alter, Senior Indebtedness, or otherwise amend or supplement in any manner
Senior Indebtedness or any instrument evidencing the same or any agreement under
which Senior Indebtedness is outstanding; (ii) sell, exchange, release or
otherwise deal with any property pledged, mortgaged or otherwise securing Senior
Indebtedness; (iii) release any person liable in any manner for the collection
of Senior Indebtedness; and (iv) exercise or refrain from exercising any rights
against the Company and any other person.

               SECTION 12.10 Notice to Trustee. The Company shall give prompt
written notice to a Responsible Officer of the Trustee at its address set forth
in Section 13.02 of any fact known to the Company which would prohibit the
making of any payment to or by the Trustee in respect of the Securities.
Notwithstanding the provisions of this Article 12 or any other provision of this
Indenture, the Trustee shall not be charged with knowledge of the existence of
any facts which would prohibit the making of any payment to or by the Trustee in
respect of the Securities, unless and until the Trustee shall have received
written notice thereof from the Company, or a holder of Senior Indebtedness or
from any trustee therefor; and, prior to the receipt of any such written notice,
the Trustee shall be entitled in all respects to assume that no such facts
exist. If the Trustee shall not have received, at least two Business Days prior
to the date upon which by the terms hereof any such monies may become payable
for any purpose (including, without limitation, the payment of the principal of,
premium, if any, or the interest on any Security) with respect to such monies,
the notice provided for in this Section, then, anything herein contained to the
contrary notwithstanding, the Trustee shall have full power and authority to
receive such monies and to apply the same to the purpose for which they were
received and shall not be effected by any notice to the contrary which may be
received by it within two Business Days prior to such date.

               The Trustee shall be entitled to rely on the delivery to it of a
written notice by a person representing himself to be a holder of Senior
Indebtedness (or a trustee therefor) to establish that such notice has been
given by a holder of Senior Indebtedness (or a trustee therefor). In the event
that the Trustee determines in good faith that further evidence is required with
respect to the right of any person as a holder of Senior Indebtedness to
participate in any payment or distribution pursuant to this Article 12, the
Trustee may request such person to

                                       64
<PAGE>   71

furnish evidence to the reasonable satisfaction of the Trustee as to the amount
of Senior Indebtedness held by such person, the extent to which such person is
entitled to participate in such payment or distribution and any other facts
pertinent to the rights of such person under this Article 12, and if such
evidence is not furnished, the Trustee may defer any payment to such person
pending judicial determination as to the right of such person to receive such
payment.

               SECTION 12.11 Reliance on Judicial Order or Certificate of
Liquidating Agent. Upon any payment or distribution of assets of the Company
referred to in this Article 12, the Trustee and the Holders of the Securities
shall be entitled to rely upon any final, nonappealable order or decree entered
by any court of competent jurisdiction in which such insolvency, bankruptcy,
receivership, liquidation, reorganization, dissolution, winding up or similar
case or proceeding is pending, or a certificate of the trustee in bankruptcy,
liquidating trustee, Custodian, receiver, assignee for the benefit of creditors,
agent or other person making such payment or distribution, delivered to the
Trustee or to the Holders of Securities, for the purpose of ascertaining the
persons entitled to participate in such payment or distribution, the holders of
the Senior Indebtedness and other indebtedness of the Company, the amount
thereof or payable thereon, the amount or amounts paid or distributed thereon
and all other facts pertinent thereto or to this Article 12.

               SECTION 12.12 Trustee Not Fiduciary for Holders of Senior
Indebtedness. The Trustee shall not be deemed to owe any fiduciary duty to the
holders of Senior Indebtedness and shall not be liable to any such holders if it
shall in good faith mistakenly pay over or distribute to Holders of Securities
or to the Company or to any other person cash, property or securities to which
any holders of Senior Indebtedness shall be entitled by virtue of this Article
12 or otherwise. The Trustee shall not be charged with knowledge of the
existence of Senior Indebtedness or of any facts that would prohibit any payment
hereunder or that would permit the resumption of any such payment unless a
Responsible Officer of the Trustee shall have received notice to that effect at
the address of the Trustee set forth in Section 13.02. With respect to the
holders of Senior Indebtedness, the Trustee undertakes to perform or to observe
only such of its covenants or obligations as are specifically set forth in this
Article 12 and no implied covenants or obligations with respect to holders of
Senior Indebtedness shall be read into this Indenture against the Trustee.

               SECTION 12.13 Rights of Trustee as Holder of Senior Indebtedness;
Preservation of Trustee's Rights. The Trustee in its individual capacity shall
be entitled to all the rights set forth in this Article 12 with respect to any
Senior Indebtedness which may at any time be held by it, to the same extent as
any other holder of Senior Indebtedness, and nothing in this Indenture shall
deprive the Trustee of any of its rights as such holder.

               Nothing in this Article shall apply to claims of, or payments to,
the Trustee under or pursuant to Section 7.07.

               SECTION 12.14 Article 12 Applicable to Paying Agents. In case at
any time any Paying Agent other than the Trustee shall have been appointed by
the Company and be then acting hereunder, the term "Trustee" as used in this
Article 12 shall in such case (unless the context otherwise requires) be
construed as extending to and including such Paying Agent within its meaning as
fully for all intents and purposes as if such Paying Agent were named in this

                                       65
<PAGE>   72

Article 12 in addition to or in place of the Trustee; provided, however, that
Sections 12.10 and 12.12 shall not apply to the Company or an Affiliate of the
Company if the Company or any such Affiliate acts as Paying Agent.

                                   ARTICLE 13

                                  MISCELLANEOUS

               SECTION 13.01 Trust Indenture Act Controls. If any provision of
this Indenture limits, qualifies, or conflicts with another provision which is
required to be included in this Indenture by the TIA, the required provision
shall control.

               SECTION 13.02 Notices. Any request, demand, authorization,
notice, waiver, consent or communication shall be in writing and delivered in
person or mailed by first-class mail, postage prepaid, addressed as follows or
transmitted by facsimile transmission (confirmed by guaranteed overnight
courier) to the following facsimile numbers:

        if to the Company:

               Allergan, Inc.
               2525 Dupont Drive
               Irvine, CA  92612
               Telephone No. (714) 246-4658
               Facsimile No. (714) 246-6987
               Attention:  General Counsel

        if to the Trustee:

               U.S. Bank Trust National Association
               100 Wall Street
               Suite 1600
               New York, NY  10005
               Telephone No. (212) 361-2524
               Facsimile No. (212) 809-5459
               Attention:  Corporate Trust Administration - Allergan, Inc.
                           Liquid Yield Option Notes due 2020 (Zero
                           Coupon-Subordinated)

               The Company or the Trustee by notice given to the other in the
manner provided above may designate additional or different addresses for
subsequent notices or communications.

               Any notice or communication given to a Securityholder shall be
mailed to the Securityholder, by first-class mail, postage prepaid, at the
Securityholder's address as it appears on the registration books of the
Registrar and shall be sufficiently given if so mailed within the time
prescribed, except that notices and communications to the Trustee shall be
effective only upon receipt.

                                       66
<PAGE>   73

               Failure to mail a notice or communication to a Securityholder or
any defect in it shall not affect its sufficiency with respect to other
Securityholders. If a notice or communication is mailed in the manner provided
above, it is duly given, whether or not received by the addressee.

               If the Company mails a notice or communication to the
Securityholders, it shall mail a copy to the Trustee and each Registrar, Paying
Agent, Conversion Agent or co-registrar.

               SECTION 13.03 Communication by Holders with Other Holders.
Securityholders may communicate pursuant to TIA Section 312(b) with other
Securityholders with respect to their rights under this Indenture or the
Securities. The Company, the Trustee, the Registrar, the Paying Agent, the
Conversion Agent and anyone else shall have the protection of TIA Section
312(c).

               SECTION 13.04 Certificate and Opinion as to Conditions Precedent.
Upon any request or application by the Company to the Trustee to take any action
under this Indenture, the Company shall furnish to the Trustee:

               (1) an Officers' Certificate stating that, in the opinion of the
               signers, all conditions precedent, if any, provided for in this
               Indenture relating to the proposed action have been complied
               with; and

               (2) an Opinion of Counsel stating that, in the opinion of such
               counsel, all such conditions precedent have been complied with.

               SECTION 13.05 Statements Required in Certificate or Opinion. Each
Officers' Certificate or Opinion of Counsel with respect to compliance with a
covenant or condition provided for in this Indenture shall include:

               (1) a statement that each person making such Officers'
               Certificate or Opinion of Counsel has read such covenant or
               condition;

               (2) a brief statement as to the nature and scope of the
               examination or investigation upon which the statements or
               opinions contained in such Officers' Certificate or Opinion of
               Counsel are based;

               (3) a statement that, in the opinion of each such person, he has
               made such examination or investigation as is necessary to enable
               such person to express an informed opinion as to whether or not
               such covenant or condition has been complied with; and

               (4) a statement that, in the opinion of such person, such
               covenant or condition has been complied with.

               SECTION 13.06 Separability Clause. In case any provision in this
Indenture or in the Securities shall be invalid, illegal or unenforceable, the
validity, legality and enforceability of the remaining provisions shall not in
any way be affected or impaired thereby.

                                       67
<PAGE>   74

               SECTION 13.07 Rules by Trustee, Paying Agent, Conversion Agent
and Registrar. The Trustee may make reasonable rules for action by or a meeting
of Securityholders. The Registrar, Conversion Agent and the Paying Agent may
make reasonable rules for their functions.

               SECTION 13.08 Legal Holidays. A "Legal Holiday" is any day other
than a Business Day. If any specified date (including a date for giving notice)
is a Legal Holiday, the action shall be taken on the next succeeding day that is
not a Legal Holiday, and, if the action to be taken on such date is a payment in
respect of the Securities, no Original Issue Discount or interest, if any, shall
accrue for the intervening period.

               SECTION 13.09 GOVERNING LAW. THE LAWS OF THE STATE OF NEW YORK
SHALL GOVERN THIS INDENTURE AND THE SECURITIES, WITHOUT REGARD TO PRINCIPLES OF
CONFLICTS OF LAWS.

               SECTION 13.10 No Recourse Against Others. A director, officer,
employee or stockholder, as such, of the Company shall not have any liability
for any obligations of the Company under the Securities or this Indenture or for
any claim based on, in respect of or by reason of such obligations or their
creation. By accepting a Security, each Securityholder shall waive and release
all such liability. The waiver and release shall be part of the consideration
for the issue of the Securities.

               SECTION 13.11 Successors. All agreements of the Company in this
Indenture and the Securities shall bind its successor. All agreements of the
Trustee in this Indenture shall bind its successor.

               SECTION 13.12 Multiple Originals. The parties may sign any number
of copies of this Indenture. Each signed copy shall be an original, but all of
them together represent the same agreement. One signed copy is enough to prove
this Indenture.

                                       68
<PAGE>   75

               IN WITNESS WHEREOF, the undersigned, being duly authorized, have
executed this Indenture on behalf of the respective parties hereto as of the
date first above written.

                                                ALLERGAN, INC.

                                                By: /s/ ERIC K. BRANDT
                                                    ----------------------------
                                                    Eric K. Brandt
                                                    Corporate Vice President and
                                                    Chief Financial Officer
Attest:

/s/ AIMEE WEISNER
--------------------------
Aimee Weisner
Corporate Counsel and
Assistant Secretary

                                       69
<PAGE>   76

               IN WITNESS WHEREOF, the undersigned, being duly authorized, has
executed this Indenture on behalf of the respective parties hereto as of the
date first above written.

[SEAL]

                                                   U.S. BANK TRUST NATIONAL
                                                   ASSOCIATION

                                                   By /s/ MARLENE J. FAHEY
                                                      --------------------------
                                                      Name: Marlene J. Fahey
                                                      Title: Vice President

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<PAGE>   77

                                  EXHIBIT A-1

                       [FORM OF FACE OF GLOBAL SECURITY]

FOR PURPOSES OF SECTIONS 1273 AND 1275 OF THE INTERNAL REVENUE CODE, THE AMOUNT
OF ORIGINAL ISSUE DISCOUNT WITH RESPECT TO EACH $1,000 OF PRINCIPAL AMOUNT AT
MATURITY OF THIS SECURITY IS $391.59, THE ISSUE DATE IS NOVEMBER 1, 2000, THE
YIELD TO MATURITY IS 2.50%.

        UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY TO THE ISSUER OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (AND ANY PAYMENT HEREON IS MADE
TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY), ANY TRANSFER PLEDGE OR OTHER
USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

        TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN
WHOLE, BUT NOT IN PART, TO NOMINEES OF THE DEPOSITORY TRUST COMPANY, OR TO A
SUCCESSOR THEREOF OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS
GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE
RESTRICTIONS SET FORTH IN ARTICLE TWO OF THE INDENTURE REFERRED TO ON THE
REVERSE HEREOF.

        THIS SECURITY AND THE SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION OF
THIS SECURITY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE "SECURITIES ACT"), OR ANY STATE SECURITIES LAWS. NEITHER THIS
SECURITY, THE SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION OF THIS SECURITY
NOR ANY INTEREST OR PARTICIPATION HEREIN OR THEREIN MAY BE REOFFERED, SOLD,
ASSIGNED, TRANSFERRED, PLEDGED, ENCUMBERED OR OTHERWISE DISPOSED OF IN THE
ABSENCE OF SUCH REGISTRATION OR UNLESS SUCH TRANSACTION IS EXEMPT FROM, OR NOT
SUBJECT TO, REGISTRATION.

        THE HOLDER OF THIS SECURITY, BY ITS ACCEPTANCE HEREOF, AGREES TO OFFER,
SELL OR OTHERWISE TRANSFER SUCH SECURITY, PRIOR TO THE DATE (THE "RESALE
RESTRICTION TERMINATION DATE") WHICH IS TWO YEARS AFTER THE LATER OF THE
ORIGINAL ISSUE DATE HEREOF AND THE LAST DATE ON WHICH THE COMPANY OR ANY
AFFILIATE OF THE COMPANY WAS THE OWNER OF ANY SECURITY (OR ANY PREDECESSOR OF
SUCH SECURITY) ONLY (A) TO THE COMPANY OR ANY SUBSIDIARY THEREOF, (B) FOR SO
LONG AS THE SECURITIES ARE ELIGIBLE FOR RESALE PURSUANT TO RULE 144A, TO A
PERSON IT

                                       A-1-1
<PAGE>   78

REASONABLY BELIEVES IS A "QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN
RULE 144A UNDER THE SECURITIES ACT THAT PURCHASES FOR ITS OWN ACCOUNT OR FOR THE
ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER TO WHICH NOTICE IS GIVEN THAT THE
TRANSFER IS BEING MADE IN RELIANCE ON RULE 144A, (C) TO AN INSTITUTIONAL
"ACCREDITED INVESTOR" WITHIN THE MEANING OF SUBPARAGRAPH (A)(1), (2),(3) OR (7)
OF RULE 501 UNDER THE SECURITIES ACT THAT IS ACQUIRING THE SECURITY FOR ITS OWN
ACCOUNT, OR FOR THE ACCOUNT OF SUCH AN INSTITUTIONAL "ACCREDITED INVESTOR," FOR
INVESTMENT PURPOSES AND NOT WITH A VIEW TO, OR FOR OFFER OR SALE IN CONNECTION
WITH, ANY DISTRIBUTION IN VIOLATION OF THE SECURITIES ACT, (D) PURSUANT TO A
REGISTRATION STATEMENT WHICH HAS BEEN DECLARED EFFECTIVE UNDER THE SECURITIES
ACT, OR (E) PURSUANT TO ANOTHER AVAILABLE EXEMPTION FROM THE REGISTRATION
REQUIREMENTS OF THE SECURITIES ACT, SUBJECT TO THE COMPANY'S AND THE TRUSTEE'S
RIGHT PRIOR TO ANY SUCH OFFER, SALE OR TRANSFER PURSUANT TO CLAUSE (C) OR (E) TO
REQUIRE THE DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATION AND/OR OTHER
INFORMATION SATISFACTORY TO EACH OF THEM, AND IN EACH OF THE FOREGOING CASES, A
CERTIFICATE OF TRANSFER IN THE FORM APPEARING ON THE OTHER SIDE OF THIS SECURITY
IS COMPLETED AND DELIVERED BY THE TRANSFEROR TO THE TRUSTEE. THIS LEGEND WILL BE
REMOVED UPON THE REQUEST OF THE HOLDER AFTER THE RESALE RESTRICTION TERMINATION
DATE.

         [THE FOREGOING LEGEND MAY BE REMOVED FROM THIS SECURITY ON SATISFACTION
OF THE CONDITIONS SPECIFIED IN THE INDENTURE.]

                                       A-1-2
<PAGE>   79

                                 ALLERGAN, INC.
                      Liquid Yield Option(TM) Note due 2020
                           (Zero Coupon-Subordinated)

No. R-                                       $
Issue Date: November 1, 2000                 CUSIP:
Issue Price:  $608.41                        Original Issue Discount: $391.59
(for each $1,000 Principal                   (for each $1,000 Principal
Amount at Maturity)                          Amount at Maturity)

        ALLERGAN, INC., a Delaware corporation, promises to pay to Cede & Co.,
or registered assigns, the Principal Amount at Maturity of ____________________
Dollars on November 1, 2020.

        This Security shall not bear interest except as specified on the other
side of this Security. Original Issue Discount will accrue as specified on the
other side of this Security. This Security is convertible as specified on the
other side of this Security.

        Additional provisions of this Security are set forth on the other side
of this Security.

Dated:                                      ALLERGAN, INC.

[SEAL]                                      By
                                              ---------------------------------
                                              Title:

Attest:

----------------------------------
Title:

TRUSTEE'S CERTIFICATE OF
  AUTHENTICATION

U.S. BANK TRUST NATIONAL ASSOCIATION
as Trustee, certifies that this
is one of the Securities referred
to in the within-mentioned Indenture.

By
  ----------------------------------
        Authorized Signatory

Dated:
      ------------------------------

                                     A-1-3
<PAGE>   80

                         [FORM OF REVERSE SIDE OF LYON]
                     Liquid Yield Option(TM) Note Due 2020
                           (Zero Coupon-Subordinated)

1.      Interest.

        This Security shall not bear interest, except as specified in this
paragraph or in paragraph 10 hereof. If the Principal Amount at Maturity hereof
or any portion of such Principal Amount at Maturity is not paid when due
(whether upon acceleration pursuant to Section 6.02 of the Indenture, upon the
date set for payment of the Redemption Price pursuant to paragraph 5 hereof,
upon the date set for payment of the Purchase Price or Change in Control
Purchase Price pursuant to paragraph 6 hereof or upon the Stated Maturity of
this Security)or if interest due hereon or any portion of such interest is not
paid when due in accordance with paragraph 10 hereof, then in each such case the
overdue amount shall, to the extent permitted by law, bear interest at the rate
of 2.50% per annum, compounded semi-annually, which interest shall accrue from
the date such overdue amount was originally due to the date payment of such
amount, including interest thereon, has been made or duly provided for. All such
interest shall be payable on demand. The accrual of such interest on overdue
amounts shall be in lieu of, and not in addition to, the continued accrual of
Original Issue Discount.

        Original Issue Discount (the difference between the Issue Price and the
Principal Amount at Maturity of the Security), in the period during which a
Security remains outstanding, shall accrue at 2.50% per annum, on a semiannual
bond equivalent basis using a 360-day year composed of twelve 30-day months,
from the Issue Date of this Security.

2.      Method of Payment.

        Subject to the terms and conditions of the Indenture, the Company will
make payments in respect of Redemption Prices, Purchase Prices, Change in
Control Purchase Prices and at Stated Maturity to Holders who surrender
Securities to a Paying Agent to collect such payments in respect of the
Securities. The Company will pay cash amounts in money of the United States that
at the time of payment is legal tender for payment of public and private debts.
However, the Company may make such cash payments by check payable in such money.

3.      Paying Agent, Conversion Agent and Registrar.

        Initially, U.S. Bank Trust National Association, a national banking
association organized under the laws of the United States (the "Trustee"), will
act as Paying Agent, Conversion Agent and Registrar. The Company may appoint and
change any Paying Agent, Conversion Agent, Registrar or co-registrar without
notice, other than notice to the Trustee except that the Company will maintain
at least one Paying Agent in the State of New York, City of New York, Borough of
Manhattan, which shall initially be an office or agency of the Trustee. The
Company or any of its Subsidiaries or any of their Affiliates may act as Paying
Agent, Conversion Agent, Registrar or co-registrar.

4.      Indenture.

                                     A-1-4

<PAGE>   81

        The Company issued the Securities under an Indenture dated as of
November 1, 2000 (the "Indenture"), between the Company and the Trustee. The
terms of the Securities include those stated in the Indenture and those made
part of the Indenture by reference to the Trust Indenture Act of 1939, as in
effect from time to time (the "TIA"). Capitalized terms used herein and not
defined herein have the meanings ascribed thereto in the Indenture. The
Securities are subject to all such terms, and Securityholders are referred to
the Indenture and the TIA for a statement of those terms.

        The Securities are general unsecured obligations of the Company limited
to $657,451,000 aggregate Principal Amount at Maturity (subject to Section 2.07
of the Indenture). The Indenture does not limit other indebtedness of the
Company, secured or unsecured.

5.      Redemption at the Option of the Company.

        No sinking fund is provided for the Securities. The Securities are
redeemable as a whole, or from time to time in part, at any time at the option
of the Company at the Redemption Prices set forth below, provided that the
Securities are not redeemable prior to November 1, 2003.

        The table below shows Redemption Prices of a Security per $1,000
Principal Amount at Maturity on the dates shown below and at Stated Maturity,
which prices reflect accrued Original Issue Discount calculated to each such
date. The Redemption Price of a Security redeemed between such dates shall
include an additional amount reflecting the additional Original Issue Discount
accrued since the next preceding date in the table.

<TABLE>
<CAPTION>

                                                (1)                 (2)               (3)
                                                             Accrued Original     Redemption
                                                LYON          Issue Discount         Price
Redemption Date                             Issue Price          at 2.50%            (1) + (2)

<S>                                      <C>                  <C>                <C>
November 1, 2003..................       $      608.41        $      47.08       $     655.49
November 1, 2004..................              608.41               63.57             671.98
November 1, 2005..................              608.41               80.48             688.89
November 1, 2006..................              608.41               97.81             706.22
November 1, 2007..................              608.41              115.57             723.98
November 1, 2008..................              608.41              133.78             742.19
November 1, 2009..................              608.41              152.46             760.87
November 1, 2010..................              608.41              171.60             780.01
November 1, 2011..................              608.41              191.22             799.63
November 1, 2012..................              608.41              211.33             819.74
November 1, 2013..................              608.41              231.96             840.37
November 1, 2014..................              608.41              253.10             861.51
November 1, 2015..................              608.41              274.77             883.18
November 1, 2016..................              608.41              296.99             905.40
November 1, 2017..................              608.41              319.76             928.17
November 1, 2018..................              608.41              343.11             951.52
November 1, 2019..................              608.41              367.05             975.46
At Stated Maturity................              608.41              391.59           1,000.00
</TABLE>

                                     A-1-5
<PAGE>   82

        If converted to a semiannual coupon note following the occurrence of a
Tax Event, this Security will be redeemable at the Restated Principal Amount
plus accrued and unpaid interest from the date of such conversion through the
Redemption Date; but in no event will this Security be redeemable before
November 1, 2003.

6.      Purchase By the Company at the Option of the Holder.

        Subject to the terms and conditions of the Indenture, the Company shall
become obligated to purchase, at the option of the Holder, the Securities held
by such Holder on the following Purchase Dates and at the following Purchase
Prices per $1,000 Principal Amount at Maturity, upon delivery of a Purchase
Notice containing the information set forth in the Indenture, at any time from
the opening of business on the date that is 20 Business Days prior to such
Purchase Date until the close of business on such Purchase Date and upon
delivery of the Securities to the Paying Agent by the Holder as set forth in the
Indenture.

<TABLE>
<CAPTION>

        Purchase Date                       Purchase Price
        -------------                       --------------

        <S>                                 <C>
        November 1, 2003                        $655.49
        November 1, 2010                        $780.01
</TABLE>

        The Purchase Price (equal to the Issue Price plus accrued Original Issue
Discount to the Purchase Date) may be paid, at the option of the Company, in
cash or by the issuance and delivery of shares of Common Stock of the Company,
or in any combination thereof.

        If prior to a Purchase Date this Security has been converted to a
semiannual coupon note following the occurrence of a Tax Event, the Purchase
Price will be equal to the Restated Principal Amount plus accrued and unpaid
interest from the date of conversion to the Purchase Date.

        At the option of the Holder and subject to the terms and conditions of
the Indenture, the Company shall become obligated to purchase the Securities
held by such Holder 35 Business Days after the occurrence of a Change in Control
of the Company occurring on or prior to November 1, 2003 for a Change in Control
Purchase Price equal to the Issue Price plus accrued Original Issue Discount to
the Change in Control Purchase Date, which Change in Control Purchase Price
shall be paid in cash. If prior to a Change in Control Purchase Date this
Security has been converted to a semiannual coupon note following the occurrence
of a Tax Event, the Change in Control Purchase Price shall be equal to the
Restated Principal Amount plus accrued and unpaid interest from the date of
conversion to the Change in Control Purchase Date.

        Holders have the right to withdraw any Purchase Notice or Change in
Control Purchase Notice, as the case may be, by delivering to the Paying Agent a
written notice of withdrawal in accordance with the provisions of the Indenture.

        If cash (and/or securities if permitted under the Indenture) sufficient
to pay the Purchase Price or Change in Control Purchase Price, as the case may
be, of all Securities or portions thereof to be purchased as of the Purchase
Date or the Change in Control Purchase Date, as the case may be, is deposited
with the Paying Agent on the Business Day following the Purchase Date or the
Change in Control Purchase Date, as the case may be, Original Issue Discount
ceases

                                     A-1-6
<PAGE>   83

to accrue on such Securities (or portions thereof) immediately after such
Purchase Date or Change in Control Purchase Date, as the case may be, and the
Holder thereof shall have no other rights as such (other than the right to
receive the Purchase Price or Change in Control Purchase Price, as the case may
be, upon surrender of such Security).

7.      Notice of Redemption.

        Notice of redemption will be mailed at least 15 days but not more than
60 days before the Redemption Date to each Holder of Securities to be redeemed
at the Holder's registered address. If money sufficient to pay the Redemption
Price of all Securities (or portions thereof) to be redeemed on the Redemption
Date is deposited with the Paying Agent prior to or on the Redemption Date,
immediately after such Redemption Date Original Issue Discount ceases to accrue
on such Securities or portions thereof. Securities in denominations larger than
$1,000 of Principal Amount at Maturity may be redeemed in part but only in
integral multiples of $1,000 of Principal Amount at Maturity.

8.      Conversion.

        Subject to the next two succeeding sentences, a Holder of a Security may
convert it into Common Stock of the Company at any time before the close of
business on November 1, 2020. If the Security is called for redemption, the
Holder may convert it at any time before the close of business on the Redemption
Date. A Security in respect of which a Holder has delivered a Purchase Notice or
Change in Control Purchase Notice exercising the option of such Holder to
require the Company to purchase such Security may be converted only if such
notice of exercise is withdrawn in accordance with the terms of the Indenture.

        The initial Conversion Rate is 5.7615 shares of Common Stock per $1,000
Principal Amount at Maturity, subject to adjustment in certain events described
in the Indenture. The Company will deliver cash or a check in lieu of any
fractional share of Common Stock.

        In the event the Company exercises its option pursuant to Section 10.01
of the Indenture to have interest in lieu of Original Issue Discount accrue on
the Security following a Tax Event, the Holder will be entitled on conversion to
receive the same number of shares of Common Stock such Holder would have
received if the Company had not exercised such option. If the Company exercises
such option, Securities surrendered for conversion during the period from the
close of business on any Regular Record Date next preceding any Interest Payment
Date to the opening of business of such Interest Payment Date (except Securities
to be redeemed on a date within such period) must be accompanied by payment of
an amount equal to the interest thereon that the registered Holder is to
receive. Except where Securities surrendered for conversion must be accompanied
by payment as described above, no interest on converted Securities will be
payable by the Company on any Interest Payment Date subsequent to the date of
conversion.

        To convert a Security, a Holder must (1) complete and manually sign the
conversion notice below (or complete and manually sign a facsimile of such
notice) and deliver such notice to the Conversion Agent, (2) surrender the
Security to the Conversion Agent, (3) furnish appropriate endorsements and
transfer documents if required by the Conversion Agent, the Company or the
Trustee and (4) pay any transfer or similar tax, if required.

                                     A-1-7
<PAGE>   84

        A Holder may convert a portion of a Security if the Principal Amount at
Maturity of such portion is $1,000 or an integral multiple of $1,000. No payment
or adjustment will be made for dividends on the Common Stock except as provided
in the Indenture. On conversion of a Security, that portion of accrued Original
Issue Discount (or interest if the Company has exercised its option provided for
in paragraph 10 hereof) attributable to the period from the Issue Date (or, if
the Company has exercised the option referred to in paragraph 10 hereof, the
later of (x) the date of such exercise and (y) the date on which interest was
last paid) through the Conversion Date with respect to the converted Security
shall not be cancelled, extinguished or forfeited, but rather shall be deemed to
be paid in full to the Holder thereof through the delivery of the Common Stock
(together with the cash payment, if any, in lieu of fractional shares) in
exchange for the Security being converted pursuant to the terms hereof; and the
fair market value of such shares of Common Stock (together with any such cash
payment in lieu of fractional shares) shall be treated as issued, to the extent
thereof, first in exchange for Original Issue Discount (or interest, if the
Company has exercised its option provided for in paragraph 10 hereof) accrued
through the Conversion Date, and the balance, if any, of such fair market value
of such Common Stock (and any such cash payment) shall be treated as issued in
exchange for the Issue Price of the Security being converted pursuant to the
provisions hereof.

        The Conversion Rate will be adjusted for dividends or distributions on
Common Stock payable in Common Stock or other Capital Stock; subdivisions,
combinations or certain reclassifications of Common Stock; distributions to all
holders of Common Stock of certain rights to purchase Common Stock for a period
expiring within 60 days at less than the Quoted Price at the Time of
Determination; and distributions to such holders of assets or debt securities of
the Company or certain rights to purchase securities of the Company (excluding
certain cash dividends or distributions). However, no adjustment need be made if
Securityholders may participate in the transaction or in certain other cases.
The Company from time to time may voluntarily increase the Conversion Rate.

        If the Company is a party to a consolidation, merger or binding share
exchange or a transfer of all or substantially all of its assets, or upon
certain distributions described in the Indenture, the right to convert a
Security into Common Stock may be changed into a right to convert it into
securities, cash or other assets of the Company or another person.

9.      Conversion Arrangement on Call for Redemption.

        Any Securities called for redemption, unless surrendered for conversion
before the close of business on the Redemption Date, may be deemed to be
purchased from the Holders of such Securities at an amount not less than the
Redemption Price, by one or more investment bankers or other purchasers who may
agree with the Company to purchase such Securities from the Holders, to convert
them into Common Stock of the Company and to make payment for such Securities to
the Trustee in trust for such Holders.

10.     Tax Event

 (a) From and after (i) the date (the "Tax Event Date") of the occurrence of a
Tax Event and (ii) the date the Company exercises such option, whichever is
later (the "Option Exercise Date"), at the option of the Company, interest in
lieu of future Original Issue Discount

                                     A-1-8
<PAGE>   85

shall accrue at the rate of 2.50% per annum on a principal amount per Security
(the "Restated Principal Amount") equal to the Issue Price plus Original Issue
Discount accrued through the Option Exercise Date and shall be payable
semiannually on November 1 and May 1 of each year (each an "Interest Payment
Date") to holders of record at the close of business on October 15 or April 15
(each a "Regular Record Date") immediately preceding such Interest Payment Date.
Interest will be computed on the basis of a 360-day year comprised of twelve
30-day months and will accrue from the most recent date to which interest has
been paid or, if no interest has been paid, from the Option Exercise Date.

         (b)   Interest on any Security that is payable, and is punctually paid
or duly provided for, on any Interest Payment Date shall be paid to the person
in whose name that Security is registered at the close of business on the
Regular Record Date for such interest at the office or agency of the Company
maintained for such purpose. Each installment of interest on any Security shall
be paid in same-day funds by transfer to an account maintained by the payee
located inside the United States.

         (c)   Except as otherwise specified with respect to the Securities, any
Defaulted Interest on any Security shall forthwith cease to be payable to the
registered Holder thereof on the relevant Regular Record Date by virtue of
having been such Holder, and such Defaulted Interest may be paid by the Company
as provided for in Section 10.02(b) of the Indenture.

11.     Denominations; Transfer; Exchange.

        The Securities are in fully registered form, without coupons, in
denominations of $1,000 of Principal Amount at Maturity and integral multiples
of $1,000. A Holder may transfer or exchange Securities in accordance with the
Indenture. The Registrar may require a Holder, among other things, to furnish
appropriate endorsements and transfer documents and to pay any taxes and fees
required by law or permitted by the Indenture. The Registrar need not transfer
or exchange any Securities selected for redemption (except, in the case of a
Security to be redeemed in part, the portion of the Security not to be redeemed)
or any Securities in respect of which a Purchase Notice or Change in Control
Purchase Notice has been given and not withdrawn (except, in the case of a
Security to be purchased in part, the portion of the Security not to be
purchased) or any Securities for a period of 15 days before a selection of
Securities to be redeemed.

12.     Persons Deemed Owners.

        The registered Holder of this Security may be treated as the owner of
this Security for all purposes.

13.     Unclaimed Money or Securities.

        The Trustee and the Paying Agent shall return to the Company upon
written request any money or securities held by them for the payment of any
amount with respect to the Securities that remains unclaimed for two years,
subject to applicable unclaimed property law. After return to the Company,
Holders entitled to the money or securities must look to the Company for payment
as general creditors unless an applicable abandoned property law designates
another person.

                                     A-1-9
<PAGE>   86

14.     Amendment; Waiver.

        Subject to certain exceptions set forth in the Indenture, (i) the
Indenture or the Securities may be amended with the written consent of the
Holders of at least a majority in aggregate Principal Amount at Maturity of the
Securities at the time outstanding and (ii) certain Defaults may be waived with
the written consent of the Holders of a majority in aggregate Principal Amount
at Maturity of the Securities at the time outstanding. Subject to certain
exceptions set forth in the Indenture, without the consent of any
Securityholder, the Company and the Trustee may amend the Indenture or the
Securities to cure any ambiguity, omission, defect or inconsistency, or to
comply with Article 5 or Section 11.14 of the Indenture, to provide for
uncertificated Securities in addition to or in place of certificated Securities
or to make any change that does not adversely affect the rights of any
Securityholder, or to comply with any requirement of the SEC in connection with
the qualification of the Indenture under the TIA.

15.     Defaults and Remedies.

        Under the Indenture, Events of Default include (i) if the Securities
have been converted to semiannual coupon notes following a Tax Event, default in
the payment of interest which default continues for a period of 30 days; (ii)
default in payment of the Principal Amount at Maturity (or, if the Securities
have been converted to semiannual coupon notes following a Tax Event, the
Restated Principal Amount), Issue Price plus accrued Original Issue Discount,
Redemption Price, Purchase Price or Change in Control Purchase Price, as the
case may be, in respect of the Securities when the same becomes due and payable;
(iii) failure by the Company to comply with other agreements in the Indenture or
the Securities, subject to notice and lapse of time; (iv) failure of the Company
to make any payment by the end of any applicable grace period after maturity of
Debt in an amount in excess of $75,000,000, or (b) the acceleration of Debt in
an amount in excess of $75,000,000 because of a default with respect to such
Debt without such Debt having been discharged or such acceleration having been
cured, waived, rescinded or annulled, subject to notice and lapse of time;
provided, however, that if any such failure or acceleration referred to in (a)
or (b) above shall cease or be cured, waived, rescinded or annulled, then the
Event of Default by reason thereof shall be deemed not to have occurred; and (v)
certain events of bankruptcy or insolvency. If an Event of Default occurs and is
continuing, the Trustee, or the Holders of at least 25% in aggregate Principal
Amount at Maturity of the Securities at the time outstanding, may declare all
the Securities to be due and payable immediately. Certain events of bankruptcy
or insolvency are Events of Default which will result in the Securities becoming
due and payable immediately upon the occurrence of such Events of Default.

        Securityholders may not enforce the Indenture or the Securities except
as provided in the Indenture. The Trustee may refuse to enforce the Indenture or
the Securities unless it receives reasonable indemnity or security. Subject to
certain limitations, Holders of a majority in aggregate Principal Amount at
Maturity of the Securities at the time outstanding may direct the Trustee in its
exercise of any trust or power. The Trustee may withhold from Securityholders
notice of any continuing Default (except a Default in payment of amounts
specified in clause (i) or (ii) above) if it determines that withholding notice
is in their interests.

                                     A-1-10
<PAGE>   87

16.     Subordination.

        The Securities are subordinated to all existing and future Senior
Indebtedness. To the extent provided in the Indenture, Senior Indebtedness must
be paid before the Securities may be paid. The Indenture does not limit the
present or future amount of Senior Indebtedness the Company may have. The
Company agrees, and each Securityholder by accepting a Security agrees, to the
subordination and authorizes the Trustee to give it effect and appoints the
Trustee as attorney-in-fact for such purpose.

17.     Trustee Dealings with the Company.

        Subject to certain limitations imposed by the TIA, the Trustee under the
Indenture, in its individual or any other capacity, may become the owner or
pledgee of Securities and may otherwise deal with and collect obligations owed
to it by the Company or its Affiliates and may otherwise deal with the Company
or its Affiliates with the same rights it would have if it were not Trustee.

18.     No Recourse Against Others.

        A director, officer, employee or stockholder, as such, of the Company
shall not have any liability for any obligations of the Company under the
Securities or the Indenture or for any claim based on, in respect of or by
reason of such obligations or their creation. By accepting a Security, each
Securityholder waives and releases all such liability. The waiver and release
are part of the consideration for the issue of the Securities.

19.     Authentication.

        This Security shall not be valid until an authorized officer of the
Trustee manually signs the Trustee's Certificate of Authentication on the other
side of this Security.

20.     Abbreviations.

        Customary abbreviations may be used in the name of a Securityholder or
an assignee, such as TEN COM (=tenants in common), TEN ENT (=tenants by the
entireties), JT TEN (=joint tenants with right of survivorship and not as
tenants in common), CUST (=custodian), and U/G/M/A (=Uniform Gift to Minors
Act).

21.     GOVERNING LAW.

        THE LAWS OF THE STATE OF NEW YORK SHALL GOVERN THE INDENTURE AND THIS
SECURITY, WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAWS.

                                ---------------

                                     A-1-11

<PAGE>   88

        The Company will furnish to any Securityholder upon written request and
without charge a copy of the Indenture which has in it the text of this Security
in larger type. Requests may be made to:

               Allergan, Inc.
               2525 Dupont Drive
               Irvine, CA  92612
               Attention:  Chief Financial Officer

                                     A-1-12

<PAGE>   89

<TABLE>
<CAPTION>

               ASSIGNMENT FORM                                                    CONVERSION NOTICE

<S>                                                              <C>
To assign this Security, fill in the form below:                 To convert this Security into Common Stock of the
                                                                 Company, check the box:

I or we assign and transfer this Security to                                           [ ]

-------------------------------------------------                To convert only part of this Security, state the
                                                                 Principal Amount at Maturity to be converted (which must
-------------------------------------------------                be $1,000 or an integral multiple of $1,000):

(Insert assignee's soc. sec. or tax ID no.)                      $
                                                                  -------------------------
-------------------------------------------------
                                                                 If you want the stock certificate made out in another
-------------------------------------------------                person's name, fill in the form below:

-------------------------------------------------                -------------------------------------------------------
(Print or type assignee's name,
address and zip code)                                            -------------------------------------------------------
                                                                 (Insert other person's soc. sec. or tax ID no.)
and irrevocably appoint
                                                                 -------------------------------------------------------
_____________________ agent to transfer this
Security on the books of the Company.                            -------------------------------------------------------
The agent may substitute another to act for him.
                                                                 -------------------------------------------------------

                                                                 -------------------------------------------------------
                                                                 (Print or type other person's name, address and zip
                                                                 code)
</TABLE>

------------------------------------------------------------------------------

Date:                         Your Signature:
     -----------------------                  --------------------------------

------------------------------------------------------------------------------
     (Sign exactly as your name appears on the other side of this Security)

Signature Guarantee:(1)
                       -------------------

----------------------
(1)     The Holder's signature must be guaranteed by an "eligible guarantor
        institution" meeting the requirements of the Registrar which
        requirements include membership or participation in the Security
        Transfer Agent Medallion Program ("STAMP") or such other "signature
        guarantee program" as may be determined by the Registrar in addition to
        or in substitution for, STAMP, all in accordance with the Securities
        Exchange Act of 1934, as amended.

                                     A-1-13
<PAGE>   90

                                   EXHIBIT A-2

                         [Form of Certificated Security]

FOR PURPOSES OF SECTIONS 1273 AND 1275 OF THE INTERNAL REVENUE CODE, THE AMOUNT
OF ORIGINAL ISSUE DISCOUNT WITH RESPECT TO EACH $1,000 OF PRINCIPAL AMOUNT AT
MATURITY OF THIS SECURITY IS $391.59, THE ISSUE DATE IS NOVEMBER 1, 2000 THE
YIELD TO MATURITY IS 2.50%.

        [INCLUDE IF SECURITY IS A CERTIFICATED SECURITY TO BE HELD BY AN
INSTITUTIONAL ACCREDITED INVESTOR--IN CONNECTION WITH ANY TRANSFER, THE HOLDER
WILL DELIVER TO THE REGISTRAR AND TRANSFER AGENT SUCH CERTIFICATES AND OTHER
INFORMATION AS SUCH TRANSFER AGENT MAY REASONABLY REQUIRE TO CONFIRM THAT THE
TRANSFER COMPLIES WITH THE FOLLOWING RESTRICTIONS.]

        THIS SECURITY AND THE SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION OF
THIS SECURITY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE "SECURITIES ACT"), OR ANY STATE SECURITIES LAWS. NEITHER THIS
SECURITY, THE SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION OF THIS SECURITY
NOR ANY INTEREST OR PARTICIPATION HEREIN OR THEREIN MAY BE REOFFERED, SOLD,
ASSIGNED, TRANSFERRED, PLEDGED, ENCUMBERED OR OTHERWISE DISPOSED OF IN THE
ABSENCE OF SUCH REGISTRATION OR UNLESS SUCH TRANSACTION IS EXEMPT FROM, OR NOT
SUBJECT TO, REGISTRATION.

        THE HOLDER OF THIS SECURITY, BY ITS ACCEPTANCE HEREOF, AGREES TO OFFER,
SELL OR OTHERWISE TRANSFER SUCH SECURITY, PRIOR TO THE DATE (THE "RESALE
RESTRICTION TERMINATION DATE") WHICH IS TWO YEARS AFTER THE LATER OF THE
ORIGINAL ISSUE DATE HEREOF AND THE LAST DATE ON WHICH THE COMPANY OR ANY
AFFILIATE OF THE COMPANY WAS THE OWNER OF ANY SECURITY (OR ANY PREDECESSOR OF
SUCH SECURITY) ONLY (A) TO THE COMPANY OR ANY SUBSIDIARY THEREOF, (B) FOR SO
LONG AS THE SECURITIES ARE ELIGIBLE FOR RESALE PURSUANT TO RULE 144A, TO A
PERSON IT REASONABLY BELIEVES IS A "QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN
RULE 144A UNDER THE SECURITIES ACT THAT PURCHASES FOR ITS OWN ACCOUNT OR FOR THE
ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER TO WHICH NOTICE IS GIVEN THAT THE
TRANSFER IS BEING MADE IN RELIANCE ON RULE 144A, (C) TO AN INSTITUTIONAL
"ACCREDITED INVESTOR" WITHIN THE MEANING OF SUBPARAGRAPH (A)(1), (2),(3) OR (7)
OF RULE 501 UNDER THE SECURITIES ACT THAT IS ACQUIRING THE SECURITY FOR ITS OWN
ACCOUNT, OR FOR THE ACCOUNT OF SUCH AN INSTITUTIONAL ACCREDITED INVESTOR," FOR
INVESTMENT PURPOSES AND NOT WITH A VIEW TO, OR FOR OFFER OR SALE IN CONNECTION
WITH, ANY DISTRIBUTION IN VIOLATION OF THE SECURITIES ACT, (D) PURSUANT TO A
REGISTRATION STATEMENT WHICH HAS BEEN DECLARED EFFECTIVE UNDER THE SECURITIES
ACT, OR (E) PURSUANT TO ANOTHER AVAILABLE EXEMPTION FROM THE REGISTRATION
REQUIREMENTS OF THE

                                     A-2-1

<PAGE>   91

SECURITIES ACT, SUBJECT TO THE COMPANY'S AND THE TRUSTEE'S RIGHT PRIOR TO ANY
SUCH OFFER, SALE OR TRANSFER, PURSUANT TO CLAUSE (C) OR (E) TO REQUIRE THE
DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATION AND/OR OTHER INFORMATION
SATISFACTORY TO EACH OF THEM, AND IN EACH OF THE FOREGOING CASES, A CERTIFICATE
OF TRANSFER IN THE FORM APPEARING ON THE OTHER SIDE OF THIS SECURITY IS
COMPLETED AND DELIVERED BY THE TRANSFEROR TO THE TRUSTEE. THIS LEGEND WILL BE
REMOVED UPON THE REQUEST OF THE HOLDER AFTER THE RESALE RESTRICTION TERMINATION
DATE.

         [THE FOREGOING LEGEND MAY BE REMOVED FROM THIS SECURITY ON SATISFACTION
OF THE CONDITIONS SPECIFIED IN THE INDENTURE.]

                                 ALLERGAN, INC.

                     Liquid Yield Option(TM) Note due 2020
                           (Zero Coupon-Subordinated)

No. R-                                      $
Issue Date: November 1, 2000.               CUSIP:
Issue Price:  $608.41                       Original Issue Discount: $391.59
(for each $1,000 Principal                  (for each $1,000 Principal
Amount at Maturity)                         Amount at Maturity)

        ALLERGAN, INC., a Delaware corporation, promises to pay to Cede & Co.,
or registered assigns, the Principal Amount at Maturity of _______Dollars on
November 1, 2020.

        This Security shall not bear interest except as specified on the other
side of this Security. Original Issue Discount will accrue as specified on the
other side of this Security. This Security is convertible as specified on the
other side of this Security.

        Additional provisions of this Security are set forth on the other side
of this Security.

Dated:                                      ALLERGAN, INC.

[SEAL]                                      By
                                              ----------------------------
                                                          Title:

Attest:

-----------------------
Title:

TRUSTEE'S CERTIFICATE OF
  AUTHENTICATION

                                     A-2-2

<PAGE>   92

U.S. BANK TRUST NATIONAL ASSOCIATION COMPANY

as Trustee, certifies that this
is one of the Securities referred
to in the within-mentioned Indenture.

By
  -----------------------------------
        Authorized Signatory

Dated:
      -------------------------------

                                     A-2-3
<PAGE>   93

                         [FORM OF REVERSE SIDE OF LYON]

                      Liquid Yield Option(TM) Note Due 2020
                           (Zero Coupon-Subordinated)

1.      Interest.

        This Security shall not bear interest, except as specified in this
paragraph or in paragraph 10 hereof. If the Principal Amount at Maturity hereof
or any portion of such Principal Amount at Maturity is not paid when due
(whether upon acceleration pursuant to Section 6.02 of the Indenture, upon the
date set for payment of the Redemption Price pursuant to paragraph 5 hereof,
upon the date set for payment of the Purchase Price or Change in Control
Purchase Price pursuant to paragraph 6 hereof or upon the Stated Maturity of
this Security)or if interest due hereon or any portion of such interest is not
paid when due in accordance with paragraph 10 hereof, then in each such case the
overdue amount shall, to the extent permitted by law, bear interest at the rate
of 2.50% per annum, compounded semi-annually, which interest shall accrue from
the date such overdue amount was originally due to the date payment of such
amount, including interest thereon, has been made or duly provided for. All such
interest shall be payable on demand. The accrual of such interest on overdue
amounts shall be in lieu of, and not in addition to, the continued accrual of
Original Issue Discount.

        Original Issue Discount (the difference between the Issue Price and the
Principal Amount at Maturity of the Security), in the period during which a
Security remains outstanding, shall accrue at 2.50% per annum, on a semiannual
bond equivalent basis using a 360-day year composed of twelve 30-day months,
from the Issue Date of this Security.

2.      Method of Payment.

        Subject to the terms and conditions of the Indenture, the Company will
make payments in respect of Redemption Prices, Purchase Prices, Change in
Control Purchase Prices and at Stated Maturity to Holders who surrender
Securities to a Paying Agent to collect such payments in respect of the
Securities. The Company will pay cash amounts in money of the United States that
at the time of payment is legal tender for payment of public and private debts.
However, the Company may make such cash payments by check payable in such money.

3.      Paying Agent, Conversion Agent and Registrar.

        Initially, U.S. Bank Trust National Association, a national banking
association organized under the laws of the United States (the "Trustee"), will
act as Paying Agent, Conversion Agent and Registrar. The Company may appoint and
change any Paying Agent, Conversion Agent, Registrar or co-registrar without
notice, other than notice to the Trustee except that the Company will maintain
at least one Paying Agent in the State of New York, City of New York, Borough of
Manhattan, which shall initially be an office or agency of the Trustee. The
Company or any of its Subsidiaries or any of their Affiliates may act as Paying
Agent, Conversion Agent, Registrar or co-registrar.

4.      Indenture.

                                     A-2-4
<PAGE>   94

        The Company issued the Securities under an Indenture dated as of
November 1, 2000 (the "Indenture"), between the Company and the Trustee. The
terms of the Securities include those stated in the Indenture and those made
part of the Indenture by reference to the Trust Indenture Act of 1939, as in
effect from time to time (the "TIA"). Capitalized terms used herein and not
defined herein have the meanings ascribed thereto in the Indenture. The
Securities are subject to all such terms, and Securityholders are referred to
the Indenture and the TIA for a statement of those terms.

        The Securities are general unsecured obligations of the Company limited
to $657,451,000 aggregate Principal Amount at Maturity (subject to Section 2.07
of the Indenture). The Indenture does not limit other indebtedness of the
Company, secured or unsecured.

5.      Redemption at the Option of the Company.

        No sinking fund is provided for the Securities. The Securities are
redeemable as a whole, or from time to time in part, at any time at the option
of the Company at the Redemption Prices set forth below, provided that the
Securities are not redeemable prior to November 1, 2003.

        The table below shows Redemption Prices of a Security per $1,000
Principal Amount at Maturity on the dates shown below and at Stated Maturity,
which prices reflect accrued Original Issue Discount calculated to each such
date. The Redemption Price of a Security redeemed between such dates shall
include an additional amount reflecting the additional Original Issue Discount
accrued since the next preceding date in the table.

<TABLE>
<CAPTION>

                                              (1)                   (2)               (3)
                                                               Accrued Original     Redemption
                                              LYON            Issue Discount         Price
Redemption Date                           Issue Price            at 2.50%            (1) + (2)

<S>                                      <C>                  <C>                <C>
November 1, 2003..................       $    608.41          $      47.08       $     655.49
November 1, 2004..................            608.41                 63.57             671.98
November 1, 2005..................            608.41                 80.48             688.89
November 1, 2006..................            608.41                 97.81             706.22
November 1, 2007..................            608.41                115.57             723.98
November 1, 2008..................            608.41                133.78             742.19
November 1, 2009..................            608.41                152.46             760.87
November 1, 2010..................            608.41                171.60             780.01
November 1, 2011..................            608.41                191.22             799.63
November 1, 2012..................            608.41                211.33             819.74
November 1, 2013..................            608.41                231.96             840.37
November 1, 2014..................            608.41                253.10             861.51
November 1, 2015..................            608.41                274.77             883.18
November 1, 2016..................            608.41                296.99             905.40
November 1, 2017..................            608.41                319.76             928.17
November 1, 2018..................            608.41                343.11             951.52
November 1, 2019..................            608.41                367.05             975.46
At Stated Maturity................            608.41                391.59           1,000.00
</TABLE>

                                     A-2-5
<PAGE>   95

        If converted to a semiannual coupon note following the occurrence of a
Tax Event, this Security will be redeemable at the Restated Principal Amount
plus accrued and unpaid interest from the date of such conversion through the
Redemption Date; but in no event will this Security be redeemable before
November 1, 2003.

6.      Purchase By the Company at the Option of the Holder.

        Subject to the terms and conditions of the Indenture, the Company shall
become obligated to purchase, at the option of the Holder, the Securities held
by such Holder on the following Purchase Dates and at the following Purchase
Prices per $1,000 Principal Amount at Maturity, upon delivery of a Purchase
Notice containing the information set forth in the Indenture, at any time from
the opening of business on the date that is 20 Business Days prior to such
Purchase Date until the close of business on such Purchase Date and upon
delivery of the Securities to the Paying Agent by the Holder as set forth in the
Indenture.

<TABLE>
<CAPTION>

    Purchase Date                           Purchase Price
    -------------                           --------------
    <S>                                     <C>
    November 1, 2003                           $655.49
    November 1, 2010                           $780.01
</TABLE>

        The Purchase Price (equal to the Issue Price plus accrued Original Issue
Discount to the Purchase Date) may be paid, at the option of the Company, in
cash or by the issuance and delivery of shares of Common Stock of the Company,
or in any combination thereof.

        If prior to a Purchase Date this Security has been converted to a
semiannual coupon note following the occurrence of a Tax Event, the Purchase
Price will be equal to the Restated Principal Amount plus accrued and unpaid
interest from the date of conversion to the Purchase Date.

        At the option of the Holder and subject to the terms and conditions of
the Indenture, the Company shall become obligated to purchase the Securities
held by such Holder 35 Business Days after the occurrence of a Change in Control
of the Company occurring on or prior to November 1, 2003 for a Change in Control
Purchase Price equal to the Issue Price plus accrued Original Issue Discount to
the Change in Control Purchase Date, which Change in Control Purchase Price
shall be paid in cash. If prior to a Change in Control Purchase Date this
Security has been converted to a semiannual coupon note following the occurrence
of a Tax Event, the Change in Control Purchase Price shall be equal to the
Restated Principal Amount plus accrued and unpaid interest from the date of
conversion to the Change in Control Purchase Date.

        Holders have the right to withdraw any Purchase Notice or Change in
Control Purchase Notice, as the case may be, by delivering to the Paying Agent a
written notice of withdrawal in accordance with the provisions of the Indenture.

        If cash (and/or securities if permitted under the Indenture) sufficient
to pay the Purchase Price or Change in Control Purchase Price, as the case may
be, of all Securities or portions thereof to be purchased as of the Purchase
Date or the Change in Control Purchase Date, as the case may be, is deposited
with the Paying Agent on the Business Day following the Purchase Date or the
Change in Control Purchase Date, as the case may be, Original Issue Discount
ceases

                                      A-2-6
<PAGE>   96

to accrue on such Securities (or portions thereof) immediately after such
Purchase Date or Change in Control Purchase Date, as the case may be, and the
Holder thereof shall have no other rights as such (other than the right to
receive the Purchase Price or Change in Control Purchase Price, as the case may
be, upon surrender of such Security).

7.      Notice of Redemption.

        Notice of redemption will be mailed at least 15 days but not more than
60 days before the Redemption Date to each Holder of Securities to be redeemed
at the Holder's registered address. If money sufficient to pay the Redemption
Price of all Securities (or portions thereof) to be redeemed on the Redemption
Date is deposited with the Paying Agent prior to or on the Redemption Date,
immediately after such Redemption Date Original Issue Discount ceases to accrue
on such Securities or portions thereof. Securities in denominations larger than
$1,000 of Principal Amount at Maturity may be redeemed in part but only in
integral multiples of $1,000 of Principal Amount at Maturity.

8.      Conversion.

        Subject to the next two succeeding sentences, a Holder of a Security may
convert it into Common Stock of the Company at any time before the close of
business on November 1, 2020. If the Security is called for redemption, the
Holder may convert it at any time before the close of business on the Redemption
Date. A Security in respect of which a Holder has delivered a Purchase Notice or
Change in Control Purchase Notice exercising the option of such Holder to
require the Company to purchase such Security may be converted only if such
notice of exercise is withdrawn in accordance with the terms of the Indenture.

        The initial Conversion Rate is 5.7615 shares of Common Stock per $1,000
Principal Amount at Maturity, subject to adjustment in certain events described
in the Indenture. The Company will deliver cash or a check in lieu of any
fractional share of Common Stock.

        In the event the Company exercises its option pursuant to Section 10.01
of the Indenture to have interest in lieu of Original Issue Discount accrue on
the Security following a Tax Event, the Holder will be entitled on conversion to
receive the same number of shares of Common Stock such Holder would have
received if the Company had not exercised such option. If the Company exercises
such option, Securities surrendered for conversion during the period from the
close of business on any Regular Record Date next preceding any Interest Payment
Date to the opening of business of such Interest Payment Date (except Securities
to be redeemed on a date within such period) must be accompanied by payment of
an amount equal to the interest thereon that the registered Holder is to
receive. Except where Securities surrendered for conversion must be accompanied
by payment as described above, no interest on converted Securities will be
payable by the Company on any Interest Payment Date subsequent to the date of
conversion.

        To convert a Security, a Holder must (1) complete and manually sign the
conversion notice below (or complete and manually sign a facsimile of such
notice) and deliver such notice to the Conversion Agent, (2) surrender the
Security to the Conversion Agent, (3) furnish appropriate endorsements and
transfer documents if required by the Conversion Agent, the Company or the
Trustee and (4) pay any transfer or similar tax, if required.

                                     A-2-7

<PAGE>   97

        A Holder may convert a portion of a Security if the Principal Amount at
Maturity of such portion is $1,000 or an integral multiple of $1,000. No payment
or adjustment will be made for dividends on the Common Stock except as provided
in the Indenture. On conversion of a Security, that portion of accrued Original
Issue Discount (or interest if the Company has exercised its option provided for
in paragraph 10 hereof) attributable to the period from the Issue Date (or, if
the Company has exercised the option referred to in paragraph 10 hereof, the
later of (x) the date of such exercise and (y) the date on which interest was
last paid) through the Conversion Date with respect to the converted Security
shall not be cancelled, extinguished or forfeited, but rather shall be deemed to
be paid in full to the Holder thereof through the delivery of the Common Stock
(together with the cash payment, if any, in lieu of fractional shares) in
exchange for the Security being converted pursuant to the terms hereof; and the
fair market value of such shares of Common Stock (together with any such cash
payment in lieu of fractional shares) shall be treated as issued, to the extent
thereof, first in exchange for Original Issue Discount (or interest, if the
Company has exercised its option provided for in paragraph 10 hereof) accrued
through the Conversion Date, and the balance, if any, of such fair market value
of such Common Stock (and any such cash payment) shall be treated as issued in
exchange for the Issue Price of the Security being converted pursuant to the
provisions hereof.

        The Conversion Rate will be adjusted for dividends or distributions on
Common Stock payable in Common Stock or other Capital Stock; subdivisions,
combinations or certain reclassifications of Common Stock; distributions to all
holders of Common Stock of certain rights to purchase Common Stock for a period
expiring within 60 days at less than the Quoted Price at the Time of
Determination; and distributions to such holders of assets or debt securities of
the Company or certain rights to purchase securities of the Company (excluding
certain cash dividends or distributions). However, no adjustment need be made if
Securityholders may participate in the transaction or in certain other cases.
The Company from time to time may voluntarily increase the Conversion Rate.

        If the Company is a party to a consolidation, merger or binding share
exchange or a transfer of all or substantially all of its assets, or upon
certain distributions described in the Indenture, the right to convert a
Security into Common Stock may be changed into a right to convert it into
securities, cash or other assets of the Company or another person.

9.      Conversion Arrangement on Call for Redemption.

        Any Securities called for redemption, unless surrendered for conversion
before the close of business on the Redemption Date, may be deemed to be
purchased from the Holders of such Securities at an amount not less than the
Redemption Price, by one or more investment bankers or other purchasers who may
agree with the Company to purchase such Securities from the Holders, to convert
them into Common Stock of the Company and to make payment for such Securities to
the Trustee in trust for such Holders.

10.     Tax Event

        (a) From and after (i) the date (the "Tax Event Date") of the occurrence
of a Tax Event and (ii) the date the Company exercises such option, whichever is
later (the "Option Exercise Date"), at the option of the Company, interest in
lieu of future Original Issue Discount

                                     A-2-8
<PAGE>   98

shall accrue at the rate of 2.50% per annum on a principal amount per Security
(the "Restated Principal Amount") equal to the Issue Price plus Original Issue
Discount accrued through the Option Exercise Date and shall be payable
semiannually on November 1 and May 1 of each year (each an "Interest Payment
Date") to holders of record at the close of business on October 15 or April 15
(each a "Regular Record Date") immediately preceding such Interest Payment Date.
Interest will be computed on the basis of a 360-day year comprised of twelve
30-day months and will accrue from the most recent date to which interest has
been paid or, if no interest has been paid, from the Option Exercise Date.

         (b) Interest on any Security that is payable, and is punctually paid or
duly provided for, on any Interest Payment Date shall be paid to the person in
whose name that Security is registered at the close of business on the Regular
Record Date for such interest at the office or agency of the Company maintained
for such purpose. Each installment of interest on any Security shall be paid in
same-day funds by transfer to an account maintained by the payee located inside
the United States.

         (c) Except as otherwise specified with respect to the Securities, any
Defaulted Interest on any Security shall forthwith cease to be payable to the
registered Holder thereof on the relevant Regular Record Date by virtue of
having been such Holder, and such Defaulted Interest may be paid by the Company
as provided for in Section 10.02(b) of the Indenture.

11.     Denominations; Transfer; Exchange.

        The Securities are in fully registered form, without coupons, in
denominations of $1,000 of Principal Amount at Maturity and integral multiples
of $1,000. A Holder may transfer or exchange Securities in accordance with the
Indenture. The Registrar may require a Holder, among other things, to furnish
appropriate endorsements and transfer documents and to pay any taxes and fees
required by law or permitted by the Indenture. The Registrar need not transfer
or exchange any Securities selected for redemption (except, in the case of a
Security to be redeemed in part, the portion of the Security not to be redeemed)
or any Securities in respect of which a Purchase Notice or Change in Control
Purchase Notice has been given and not withdrawn (except, in the case of a
Security to be purchased in part, the portion of the Security not to be
purchased) or any Securities for a period of 15 days before a selection of
Securities to be redeemed.

12.     Persons Deemed Owners.

        The registered Holder of this Security may be treated as the owner of
this Security for all purposes.

13.     Unclaimed Money or Securities.

        The Trustee and the Paying Agent shall return to the Company upon
written request any money or securities held by them for the payment of any
amount with respect to the Securities that remains unclaimed for two years,
subject to applicable unclaimed property law. After return to the Company,
Holders entitled to the money or securities must look to the Company for payment
as general creditors unless an applicable abandoned property law designates
another person.

                                     A-2-9

<PAGE>   99

14.     Amendment; Waiver.

        Subject to certain exceptions set forth in the Indenture, (i) the
Indenture or the Securities may be amended with the written consent of the
Holders of at least a majority in aggregate Principal Amount at Maturity of the
Securities at the time outstanding and (ii) certain Defaults may be waived with
the written consent of the Holders of a majority in aggregate Principal Amount
at Maturity of the Securities at the time outstanding. Subject to certain
exceptions set forth in the Indenture, without the consent of any
Securityholder, the Company and the Trustee may amend the Indenture or the
Securities to cure any ambiguity, omission, defect or inconsistency, or to
comply with Article 5 or Section 11.14 of the Indenture, to provide for
uncertificated Securities in addition to or in place of certificated Securities
or to make any change that does not adversely affect the rights of any
Securityholder, or to comply with any requirement of the SEC in connection with
the qualification of the Indenture under the TIA.

15.     Defaults and Remedies.

        Under the Indenture, Events of Default include (i) if the Securities
have been converted to semiannual coupon notes following a Tax Event, default in
the payment of interest which default continues for a period of 30 days; (ii)
default in payment of the Principal Amount at Maturity (or, if the Securities
have been converted to semiannual coupon notes following a Tax Event, the
Restated Principal Amount), Issue Price plus accrued Original Issue Discount,
Redemption Price, Purchase Price or Change in Control Purchase Price, as the
case may be, in respect of the Securities when the same becomes due and payable;
(iii) failure by the Company to comply with other agreements in the Indenture or
the Securities, subject to notice and lapse of time; (iv) failure of the Company
to make any payment by the end of any applicable grace period after maturity of
Debt in an amount in excess of $75,000,000, or (b) the acceleration of Debt in
an amount in excess of $75,000,000 because of a default with respect to such
Debt without such Debt having been discharged or such acceleration having been
cured, waived, rescinded or annulled, subject to notice and lapse of time;
provided, however, that if any such failure or acceleration referred to in (a)
or (b) above shall cease or be cured, waived, rescinded or annulled, then the
Event of Default by reason thereof shall be deemed not to have occurred; and (v)
certain events of bankruptcy or insolvency. If an Event of Default occurs and is
continuing, the Trustee, or the Holders of at least 25% in aggregate Principal
Amount at Maturity of the Securities at the time outstanding, may declare all
the Securities to be due and payable immediately. Certain events of bankruptcy
or insolvency are Events of Default which will result in the Securities becoming
due and payable immediately upon the occurrence of such Events of Default.

        Securityholders may not enforce the Indenture or the Securities except
as provided in the Indenture. The Trustee may refuse to enforce the Indenture or
the Securities unless it receives reasonable indemnity or security. Subject to
certain limitations, Holders of a majority in aggregate Principal Amount at
Maturity of the Securities at the time outstanding may direct the Trustee in its
exercise of any trust or power. The Trustee may withhold from Securityholders
notice of any continuing Default (except a Default in payment of amounts
specified in clause (i) or (ii) above) if it determines that withholding notice
is in their interests.

                                     A-2-10
<PAGE>   100

16.     Subordination.

        The Securities are subordinated to all existing and future Senior
Indebtedness. To the extent provided in the Indenture, Senior Indebtedness must
be paid before the Securities may be paid. The Indenture does not limit the
present or future amount of Senior Indebtedness the Company may have. The
Company agrees, and each Securityholder by accepting a Security agrees, to the
subordination and authorizes the Trustee to give it effect and appoints the
Trustee as attorney-in-fact for such purpose.

17.     Trustee Dealings with the Company.

        Subject to certain limitations imposed by the TIA, the Trustee under the
Indenture, in its individual or any other capacity, may become the owner or
pledgee of Securities and may otherwise deal with and collect obligations owed
to it by the Company or its Affiliates and may otherwise deal with the Company
or its Affiliates with the same rights it would have if it were not Trustee.

18.     No Recourse Against Others.

        A director, officer, employee or stockholder, as such, of the Company
shall not have any liability for any obligations of the Company under the
Securities or the Indenture or for any claim based on, in respect of or by
reason of such obligations or their creation. By accepting a Security, each
Securityholder waives and releases all such liability. The waiver and release
are part of the consideration for the issue of the Securities.

19.     Authentication.

        This Security shall not be valid until an authorized officer of the
Trustee manually signs the Trustee's Certificate of Authentication on the other
side of this Security.

20.     Abbreviations.

        Customary abbreviations may be used in the name of a Securityholder or
an assignee, such as TEN COM (=tenants in common), TEN ENT (=tenants by the
entireties), JT TEN (=joint tenants with right of survivorship and not as
tenants in common), CUST (=custodian), and U/G/M/A (=Uniform Gift to Minors
Act).

21.     GOVERNING LAW.

THE LAWS OF THE STATE OF NEW YORK SHALL GOVERN THE INDENTURE AND THIS SECURITY,
WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAWS.

                              --------------------

                                     A-2-11
<PAGE>   101

The Company will furnish to any Securityholder upon written request and without
charge a copy of the Indenture which has in it the text of this Security in
larger type. Requests may be made to:

               Allergan, Inc.
               2525 Dupont Drive
               Irvine, CA  92612
               Attention:  Chief Financial Officer

                                     A-2-12

<PAGE>   102
<TABLE>
<CAPTION>

               ASSIGNMENT FORM                                                    CONVERSION NOTICE

<S>                                                              <C>
To assign this Security, fill in the form below:                 To convert this Security into Common Stock of the
                                                                 Company, check the box:

I or we assign and transfer this Security to                                           [ ]

-------------------------------------------------                To convert only part of this Security, state the
                                                                 Principal Amount at Maturity to be converted (which must
-------------------------------------------------                be $1,000 or an integral multiple of $1,000):

(Insert assignee's soc. sec. or tax ID no.)                      $
                                                                  -------------------------
-------------------------------------------------
                                                                 If you want the stock certificate made out in another
-------------------------------------------------                person's name, fill in the form below:

-------------------------------------------------                -------------------------------------------------------
(Print or type assignee's name,
address and zip code)                                            -------------------------------------------------------
                                                                 (Insert other person's soc. sec. or tax ID no.)
and irrevocably appoint
                                                                 -------------------------------------------------------
_____________________ agent to transfer this
Security on the books of the Company.                            -------------------------------------------------------
The agent may substitute another to act for him.
                                                                 -------------------------------------------------------

                                                                 -------------------------------------------------------
                                                                 (Print or type other person's name, address and zip
                                                                 code)
</TABLE>

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Date:                         Your Signature:
     -----------------------                  --------------------------------

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     (Sign exactly as your name appears on the other side of this Security)

Signature Guarantee:(2)
                       -------------------------

---------------

(2)     The Holder's signature must be guaranteed by an "eligible guarantor
        institution" meeting the requirements of the Registrar which
        requirements include membership or participation in the Security
        Transfer Agent Medallion Program ("STAMP") or such other "signature
        guarantee program" as may be determined by the Registrar in addition to
        or in substitution for, STAMP, all in accordance with the Securities
        Exchange Act of 1934, as amended.

                                     A-2-13
<PAGE>   103

                                   EXHIBIT B-1
                              TRANSFER CERTIFICATE

        In connection with any transfer of any of the Securities within the
period prior to the expiration of the holding period applicable to the sales
thereof under Rule 144(k) under the Securities Act of 1933, as amended (the
"Securities Act") (or any successor provision), the undersigned registered owner
of this Security hereby certifies with respect to $____________ Principal Amount
at Maturity of the above-captioned securities presented or surrendered on the
date hereof (the "Surrendered Securities") for registration of transfer, or for
exchange or conversion where the securities issuable upon such exchange or
conversion are to be registered in a name other than that of the undersigned
registered owner (each such transaction being a "transfer"), that such transfer
complies with the restrictive legend set forth on the face of the Surrendered
Securities for the reason checked below:

        [ ]     The transfer of the Surrendered Securities complies with Rule
                144 under the U.S. Securities Act of 1933, as amended (the
                "Securities Act"); or

        [ ]     The transfer of the Surrendered Securities complies with Rule
                144A under the Securities Act; or

        [ ]     The transfer of the Surrendered Securities is to an
                institutional accredited investor, as described in Rule
                501(a)(1), (2), (3) or (7) of Regulation D under the Securities
                Act; or

        [ ]     The transfer of the Surrendered Securities is pursuant to an
                effective registration statement under the Securities Act.

        and unless the box below is checked, the undersigned confirms that, to
the undersigned's knowledge, such Securities are not being transferred to an
"affiliate" of the Company as defined in Rule 144 under the Securities Act (an
"Affiliate").

        [ ]     The transferee is an Affiliate of the Company.

DATE:
     --------------------                    -----------------------------------
                                                       Signature(s)

            (If the registered owner is a corporation, partnership or
             fiduciary, the title of the person signing on behalf of
                     such registered owner must be stated.)

                                     B-1-1
<PAGE>   104

                                   EXHIBIT B-2

             FORM OF LETTER TO BE DELIVERED BY ACCREDITED INVESTORS

Allergan, Inc.
2525 Dupont Drive
Irvine, CA  92612

U.S. Bank Trust National Association
100 Wall Street, Suite 1600
New York, NY  10005
Attn:   Corporate Trust Administration-
        Allergan, Inc. Liquid Yield Option
        Notes due 2020 (Zero Coupon-Subordinated)

Dear Sirs:

        We are delivering this letter in connection with the proposed transfer
of $_____________ Principal Amount at Maturity of the Liquid Yield Option Notes
due 2020 ("LYONs") of Allergan, Inc. (the "Company"), which are convertible into
shares of the Company's Common Stock, $0.01 par value per share (the "Common
Stock").

        We hereby confirm that:

               (i) we are an "accredited investor" within the meaning of Rule
        501(a)(1), (2) or (3) under the Securities Act of 1933, as amended (the
        "Securities Act"), or an entity in which all of the equity owners are
        accredited investors within the meaning of Rule 501(a)(1), (2) or (3)
        under the Securities Act (an "Institutional Accredited Investor");

               (ii) the purchase of LYONs by us is for our own account or for
        the account of one or more other Institutional Accredited Investors or
        as fiduciary for the account of one or more trusts, each of which is an
        "accredited investor" within the meaning of Rule 501(a)(7) under the
        Securities Act and for each of which we exercise sole investment
        discretion or (B) we are a "bank," within the meaning of Section 3(a)(2)
        of the Securities Act, or a "savings and loan association" or other
        institution described in Section 3(a)(5)(A) of the Securities Act that
        is acquiring LYONs as fiduciary for the account of one or more
        institutions for which we exercise sole investment discretion;

               (iii) we will acquire LYONs having a minimum principal amount at
        maturity of not less than $250,000 for our own account or for any
        separate account for which we are acting;

               (iv) we have such knowledge and experience in financial and
        business matters that we are capable of evaluating the merits and risks
        of purchasing LYONs; and

                                     B-2-1
<PAGE>   105

               (v) we are not acquiring LYONs with a view to distribution
        thereof or with any present intention of offering or selling LYONs or
        the Common Stock issuable upon conversion thereof, except as permitted
        below; provided that the disposition of our property and property of any
        accounts for which we are acting as fiduciary shall remain at all times
        within our control.

        We understand that the LYONs were originally offered and sold in a
transaction not involving any public offering within the United States within
the meaning of the Securities Act and that the LYONs and the shares of Common
Stock (the "Securities") issuable upon conversion thereof have not been
registered under the Securities Act, and we agree, on our own behalf and on
behalf of each account for which we acquire any LYONs, that if in the future we
decide to resell or otherwise transfer such Securities prior to the date (the
"Resale Restriction Termination Date") which is two years after the later of the
original issuance of the LYONs and the last date on which the Company or an
affiliate of the Company was the owner of the Security, such Securities may be
resold or otherwise transferred only (i) to Allergan, Inc. or any subsidiary
thereof, or (ii) for as long as the LYONs are eligible for resale pursuant to
Rule 144A, to a person it reasonably believes is a "qualified institutional
buyer" (as defined in Rule 144A under the Securities Act) that purchases for its
own account or for the account of a qualified institutional buyer to which
notice is given that the transfer is being made in reliance on Rule 144A, or
(iii) to an Institutional Accredited Investor that is acquiring the Security for
its own account, or for the account of such Institutional Accredited Investor
for investment purposes and not with a view to, or for offer or sale in
connection with, any distribution in violation of the Securities Act, or (iv)
pursuant to another available exemption from registration under the Securities
Act (if applicable), or (v) pursuant to a registration statement which has been
declared effective under the Securities Act and, in each case, in accordance
with any applicable securities laws of any State of the United States or any
other applicable jurisdiction and in accordance with the legends set forth on
the Securities. We further agree to provide any person purchasing any of the
Securities other than pursuant to clause (v) above from us a notice advising
such purchaser that resales of such securities are restricted as stated herein.
We understand that the trustee or the transfer agent, as the case may be, for
the Securities will not be required to accept for registration of transfer any
Securities pursuant to (iii) or (iv) above except upon presentation of evidence
satisfactory to the Company that the foregoing restrictions on transfer have
been complied with. We further understand that any Securities will be in the
form of definitive physical certificates and that such certificates will bear a
legend reflecting the substance of this paragraph other than certificates
representing Securities transferred pursuant to clause (v) above.

        We acknowledge that the Company, others and you will rely upon our
confirmations, acknowledgments and agreements set forth herein, and we agree to
notify you promptly in writing if any of our representations or warranties
herein ceases to be accurate and complete.

                                     B-2-2

<PAGE>   106

        THIS LETTER SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE
INTERNAL LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO PRINCIPLES OF
CONFLICTS OF LAWS.

                                            ------------------------------------
                                            (Name of Purchaser)

                                             By:
                                                --------------------------------
                                                Name:
                                                Title:
                                                Address:

                                     B-2-3

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