Document:

<PAGE>

                                                                     Exhibit 4.6

THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 OR ANY
STATE SECURITIES LAWS. THIS WARRANT HAS BEEN ACQUIRED FOR INVESTMENT AND NOT
WITH A VIEW TO DISTRIBUTION OR RESALE, AND MAY NOT BE SOLD OR OTHERWISE
TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION STATEMENT FOR SUCH SHARES UNDER
THE SECURITIES ACT OF 1933 AND ANY APPLICABLE STATE SECURITIES LAWS, OR EVIDENCE
REASONABLY SATISFACTORY TO THE COMPANY THAT REGISTRATION IS NOT REQUIRED UNDER
SUCH ACT AND LAWS.

Warrant No. S1-(WarrantNo)                                    (Warrants) Shares

                              COMMON STOCK WARRANT

                              To Purchase Shares of

                                  Common Stock

                                       of

                           SPECTRA SCIENCE CORPORATION

     THIS CERTIFIES THAT, for value received, (Shareholder) ("Holder"), or
Holder's assigns, is entitled, subject to the terms set forth below, to purchase
from Spectra Science Corporation, a Delaware corporation (the "Company"),
formerly known as Spectra Acquisition Corp., (WarrantsSpelledOut) ((Warrants))
fully paid and non-assessable shares of the Common Stock, $.01 par value per
share ("Common Stock"), of the Company at a purchase price of $2.00 per share
(subject to adjustment as set forth herein, the "Warrant Price"). The number and
character of, and purchase price for, such shares of Common Stock are subject to
adjustment as provided herein. This Warrant will become exercisable upon the
first to occur of (a) the closing (a "Public Offering Closing") of the first
firm commitment underwritten public offering (a "Public Offering") of Common
Stock by the Company in which the aggregate net proceeds to the Company shall
not be less than $10,000,000 and the price per share of Common Stock to the
public shall be not less than $3.00 per share (a "Public Offering Closing") or
(b) the closing of (i) a consolidation or merger or other business combination
to which the Company is a party and in which the Company is not the surviving
corporation or in which more than 50% of the equity ownership of the Company
(calculated on a fully diluted basis) has been transferred and (ii) the closing
of the sale of all or substantially all of the assets of the Company (any of the
transactions

<PAGE>

describe in clauses (i) and (ii) being referred to in this Warrant as an
"Acquisition Transaction"). This Warrant will remain exercisable following a
Public Offering Closing until and unless this Warrant has expired as provided
herein. This Warrant will be canceled if not exercised in connection with the
closing of an Acquisition Transaction as provided herein. If not otherwise
exercisable or canceled, this Warrant will be exercisable at any time within
sixty (60) days prior to the expiration date provided for in Section 1.3 hereof.

     This Warrant was originally issued pursuant to an Asset Purchase Agreement,
dated as of July 15, 1996, between the Company and SSC Science Corporation, a
Delaware corporation, formerly known as Spectra Science Corporation, and was
transferred to the Holder hereof on January 18, 2001.

     1.   Exercise of Warrant.

          1.1  Full Exercise. This Warrant may be exercised by the Holder hereof
in whole by the surrender of this Warrant and delivery of an executed Notice of
Exercise in the form appended hereto duly executed by such Holder to the Company
at its principal office at any time or times within the period specified above,
accompanied by payment for the Common Stock as to which this Warrant is being
exercised by wire transfer to an account designated by the Company or by
certified or bank check. Alternatively, the Holder hereof may elect to exercise
the rights represented by this Warrant in whole by the surrender of this Warrant
and delivery of an executed Notice of Exercise specifying that the value (as
determined below) of this Warrant shall be the consideration for the shares of
Common Stock, in which event the Company shall issue to the Holder a number of
shares of Common Stock computed using the following formula:

     X = Y (A-B)
         -------
            A

Where: X = the number of shares of Common Stock to be issued to the Holder.
       Y = the number of shares of Common Stock issuable upon exercise of this
           Warrant on the date of delivery of the Notice of Exercise.
       A = the current fair market value of one share of Common Stock.
       B = Warrant Price.

     As used herein, current fair market value of the Common Stock shall mean
the numerical average of fair market value per share of Common Stock over a
period of 21 days consisting of the day on which the Notice of Exercise is
received by the Company and the 20 consecutive business days prior to such day.
The fair market value per share of Common Stock for any day shall mean the
average of the closing prices of the Company's Common Stock sold on all
securities exchanges on which the Common Stock may at the time be listed or as
quoted on the Nasdaq National Market, or, if there have been no sales on any
such exchange or any such quotation on any day, the average of the highest bid
and lowest asked prices on all such exchanges or such System at the end of such
day, or, if on any day the Common Stock is not so

                                      -2-

<PAGE>

listed, the average of the representative bid and asked prices quoted in the
Nasdaq system as of 4:00 p.m., New York City time, or, if on any day the Common
Stock is not quoted in the Nasdaq system, the average of the highest bid and
lowest asked price on such day in the domestic over-the-counter market as
reported by the National Quotation Bureau, Incorporated, or any similar
successor organization. If at any time the Common Stock is not listed on any
securities exchange or quoted in the Nasdaq system or the over-the-counter
market, the current fair market value of Common Stock shall be the highest price
per share which the Company could obtain from a willing buyer (not a current
employee or director) for shares of Common Stock sold by the Company, from
authorized but unissued shares, as determined in good faith by the Board of
Directors of the Company. Notwithstanding the foregoing, if the Company shall
engage in an Acquisition Transaction, the current fair market value of the
Common Stock shall be determined with reference to the value ascribed to the
Company by the terms of the Acquisition Transaction.

          1.2  Delivery of Stock Certificates, etc., on Exercise. As soon as
practicable after the exercise of this Warrant in full and in any event within
10 days thereafter, the Company at its expense will cause to be issued in the
name of and delivered to the Holder hereof, or as such Holder (upon payment by
such Holder of any applicable transfer taxes) may direct, a certificate or
certificates for the number of fully paid and nonassessable shares of Common
Stock to which such Holder shall be entitled on such exercise.

          1.3  Expiration. Unless canceled in connection with an Acquisition
Transaction, this Warrant will expire on August 26, 2006 at 5:00 p.m., Eastern
Standard Time.

          1.4  Company Rights After Public Offering Closing. At any time after
one (1) year after a Public Offering Closing, the Company may give written
notice of not less than twenty (20) days (the "Notice Period") to the Holder
hereof that this Warrant will automatically terminate unless exercised during
such Notice Period; provided that, (i) the shares of Common Stock issuable upon
exercise of this Warrant must be either registered for sale under the Securities
Act of 1933, as amended, or eligible for sale under Rule 144 under that Act;
(ii) the last sales price of the Common Stock for each of the consecutive twenty
(20) business days preceding the commencement of the Notice Period shall have
been not less than $5.00 per share; and (iii) the average of the last sales
price of the Common Stock during the Notice Period shall have been not less than
$5.00 per share. If the foregoing provisions are met, and this Warrant is not
exercised within the Notice Period, this Warrant will terminate automatically
and be canceled.

     2.   Adjustments for Certain Events.

          2.1  Stock Splits, etc. In case the Company shall at any time
subdivide its outstanding shares of Common Stock into a greater number of
shares, the Warrant Price in effect immediately prior to such subdivision shall
be proportionately reduced, and the number of shares of Common Stock issuable
upon exercise of this Warrant shall be proportionately increased; and
conversely, in case the outstanding shares of Common Stock of the Company shall
be combined

                                      -3-

<PAGE>

into a smaller number of shares, the Warrant Price in effect immediately prior
to such combination shall be proportionately increased and the number of shares
of Common Stock issuable upon exercise of this Warrant shall be proportionately
reduced.

          2.2  Adjustments for Capital Reorganization or Reclassification. If
any capital reorganization or reclassification of the capital stock of the
Company shall be effected, then, as a condition of such capital reorganization
or reclassification, lawful and adequate provision shall be made whereby the
Holder hereof shall thereafter have the right to purchase and receive upon the
basis and upon the terms and conditions specified in this Warrant, in lieu of
shares of Common Stock of the Company immediately theretofore purchasable and
receivable upon the exercise of the rights represented hereby, those shares of
stock, securities or assets which would have been issued or payable with respect
to or in exchange for the Common Stock issuable upon exercise of this Warrant
had this Warrant been exercised immediately prior to the record date (or the
effective date, as the case may be) for such capital reorganization or
reclassification.

          2.3  Acquisition Transaction. The Company shall provide to the Holder
of this Warrant written notice not less than thirty (30) business days prior to
the anticipated closing of an Acquisition Transaction of the anticipated closing
of such transaction and a brief summary of the business terms thereof. The
Holder of this Warrant will in such case be entitled to exercise this Warrant,
effective immediately prior to the closing of the Acquisition Transaction
(subject to the completion of such closing), as provided in Section 1.1 hereof
by delivery of an executed Notice of Exercise and payment of the exercise price
not less than five (5) days prior to such closing. In the event the closing of
an Acquisition Transaction does not occur for any reason, such Notice of
Exercise will be of no force or effect.

          2.4  Notice of Adjustments. Upon any adjustment of the Warrant Price,
the Company shall give written notice thereof, by first class mail, postage
prepaid, addressed to the Holder of this Warrant at its address registered on
the books of the Company, which notice shall state the Warrant Price resulting
from such adjustment and the increased or decreased number of shares purchasable
at such price upon the exercise of this Warrant, setting forth in reasonable
detail the method of calculation and the facts upon which such calculation is
based.

     3.   Liquidating Dividends. If the Company pays a dividend or makes a
distribution on the Common Stock payable otherwise than in cash out of earnings
or earned surplus (determined in accordance with generally accepted accounting
principles) except for a stock dividend payable in shares of Common Stock (a
"Liquidating Dividend"), then the Company will pay or distribute to the Holder
of this Warrant, upon the exercise hereof, in addition to the Common Stock
purchased upon such exercise, the Liquidating Dividend which would have been
paid to such Holder if it had been the owner of record of such shares of Common
Stock immediately prior to the date on which a record is taken for such
Liquidating Dividend or, if no record is taken, the date as of which the record
holders of Common Stock entitled to such dividends or distribution are to be
determined.

                                      -4-

<PAGE>

     4.   Notice of Liquidation, etc. In the event of any voluntary or
involuntary dissolution, liquidation or winding-up of the Company, the Company
not less than ten (10) days prior to the occurrence of such event will give to
the Holder of this Warrant written notice of (i) the date on which any such
dissolution, liquidation or winding-up is to take place, (ii) the amount and
character of assets, including any stock or other securities, proposed to be
issued or granted and (iii) the persons or class of persons to whom such
proposed issue or grant is to be made.

     5.   Notice of Public Offering Closing; Lock-up. The Company will give to
the Holder of this Warrant written notice of the anticipated date of a Public
Offering Closing not less than five (5) days prior to such closing. Holder
agrees not to sell or otherwise transfer any shares of Common Stock issued or
issuable upon exercise of this Warrant for a period of up to 180 days following
a Public Offering Closing, provided the underwriters of the Public Offering have
requested that directors, executive officers and other stockholders of the
Company agree not to sell or transfer shares of Common Stock during such period.

     6.   Reservation of Stock, etc., Issuable on Exercise of Warrants. The
Company will at all times reserve and keep available, solely for issuance and
delivery on the exercise of the Warrant, all shares of Common Stock from time to
time issuable on the exercise of the Warrant.

     7.   Voting Rights. This Warrant shall not entitle the Holder hereof to
voting rights or any other rights whatsoever as a stockholder of the Company or,
except as set forth in Section 4 above, to any notice of meetings of
stockholders or any other proceedings of the Company.

     8.   Exchange of Warrant. Subject to compliance with applicable securities
laws, this Warrant is exchangeable, upon the surrender hereof at the principal
office of the Company, for new Warrants of like tenor representing in the
aggregate the right to subscribe for and purchase the number of shares of Common
Stock which may be subscribed for and purchased hereunder, each of such new
Warrants to represent the right to subscribe for and purchase such number of
shares of Common Stock as shall be designated by such Holder hereof at the time
of such surrender.

     9.   Transferability. Subject to compliance with applicable securities
laws, this Warrant and all rights hereunder are transferable at the principal
office of the Company by the Holder hereof in person or by duly authorized
attorney, upon surrender of this Warrant properly endorsed, together with a
written assignment of this Warrant duly executed by the Holder hereof or its
duly authorized attorney. Each taker and Holder of this Warrant, by taking or
holding the same, consents and agrees that this Warrant, when endorsed in blank,
shall be deemed negotiable, and that the Holder hereof, when this Warrant shall
have been so endorsed, may be treated by the Company and all other persons
dealing with this Warrant as the absolute owner hereof for any purpose and as
the person entitled to exercise the rights represented by this

                                      -5-

<PAGE>

Warrant, or to the transfer hereof on the books of the Company, any notice to
the contrary notwithstanding; but until such transfer on such books, the Company
may treat the Holder hereof as the owner for all purposes.

     10.  Miscellaneous. The provisions of this Warrant may be amended or waived
only by an instrument in writing signed by the party against which enforcement
of such amendment or waiver is sought. This Warrant shall be construed and
enforced in accordance with and governed by the laws of the Commonwealth of
Massachusetts. The headings in this Warrant are for purposes of reference only,
and shall not limit or otherwise affect any of the terms hereof. This Warrant is
being executed as an instrument under seal. The invalidity or unenforceability
of any provision hereof shall in no way affect the validity or enforceability of
any other provision.

     IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by an
officer thereunto duly authorized as of January 18, 2001.

                                             SPECTRA SCIENCE CORPORATION

                                             By:________________________________
                                                Nabil Lawandy, President
Attest:

___________________________

                                      -6-

<PAGE>

                               NOTICE OF EXERCISE

                               (To be Executed by
                              the Registered Holder
                        in Order to Exercise the Warrant)

     The undersigned hereby irrevocably elects to exercise the right to purchase
______________________________ (_________) shares of Common Stock, $.01 par
value, of Spectra Science Corporation, a Delaware corporation, formerly known as
Spectra Acquisition Corp., covered by Warrant No. S1-[_] according to the
conditions thereof and herewith makes payment of the Warrant Price of such
shares in full.

     Specify method of exercise by check mark:

1. Such payment is hereby made in the amount of $________ by wire transfer or by
   certified or bank check.

2. The Holder elects to receive shares for the value (as determined pursuant to
   Section 1.1 of the Warrant) of the Warrant.

                               Printed Name
                               of Warrant Holder:  ____________________________

                               Signature:          ____________________________

                               Title (if signing
                               on behalf of a
                               Warrant Holder:     ____________________________

                               Address:            ____________________________

                                                   ____________________________

                                                   ____________________________

                                                   ____________________________

Dated:__________________

                                      -7-<PAGE>

                                                                     Exhibit 4.7

NEITHER THIS WARRANT NOR ANY SECURITIES PURCHASABLE UPON EXERCISE HEREOF HAVE
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 OR ANY STATE SECURITIES LAWS.
THIS WARRANT HAS BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO
DISTRIBUTION OR RESALE, AND NEITHER THIS WARRANT NOR ANY SECURITIES PURCHASABLE
UPON EXERCISE HEREOF MAY BE SOLD OR OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE
REGISTRATION STATEMENT FOR SUCH SHARES UNDER THE SECURITIES ACT OF 1933 AND ANY
APPLICABLE STATE SECURITIES LAWS, OR EVIDENCE REASONABLY SATISFACTORY TO THE
COMPANY THAT REGISTRATION IS NOT REQUIRED UNDER SUCH ACT AND LAWS.

Warrant No. W-[___]                                           [_________] Shares

                              COMMON STOCK WARRANT

                             To Purchase Shares of

                                  Common Stock

                                       of

                          SPECTRA SCIENCE CORPORATION

     THIS CERTIFIES THAT, for value received, [_______] ("Holder"), or his
assigns, is entitled, subject to the terms set forth below, to purchase from
Spectra Science Corporation (the "Company"), [__________________] fully paid and
non-assessable shares of the Common Stock, $.01 par value per share ("Common
Stock"), of the Company at a purchase price of $4.00 per share (subject to
adjustment as set forth herein, the "Warrant Price"). The number and character
of, and purchase price for, such shares of Common Stock are subject to
adjustment as provided herein. This Warrant is immediately exercisable and will
remain exercisable until and unless this Warrant has expired as provided herein.

     This Warrant has been issued pursuant to a Series B Convertible Preferred
Stock Purchase Agreement, dated as of July 25, 1997, between the Company and the
persons named as Purchasers therein.

<PAGE>

     1. Exercise of Warrant.

          1.1 Exercise. This Warrant may be exercised by the holder hereof in
whole or in part (but not as to fractional shares of Common Stock) by the
surrender of this Warrant and delivery of an executed Notice of Exercise in the
form appended hereto duly executed by such holder to the Company at its
principal office at any time or times within the period specified above,
accompanied by payment for the Common Stock as to which this Warrant is being
exercised by wire transfer to an account designated by the Company or by
certified or bank check. In the event of a partial exercise of this Warrant,
this Warrant will be canceled and the Company will deliver a new Warrant of like
tenor representing the balance of the share of Common Stock purchasable
hereunder. Alternatively, the holder hereof may elect to exercise the rights
represented by this Warrant in whole or in part (but not as to fractional shares
of Common Stock) by the surrender of this Warrant and delivery of an executed
Notice of Exercise specifying that the value (as determined below) of this
Warrant shall be the consideration for the shares of Common Stock, in which
event the Company shall issue to the holder a number of shares of Common Stock
computed using the following formula:

       X = Y (A-B)
           -------
              A

Where: X = the number of shares of Common Stock to be issued to the holder.
       Y = the number of shares of Common Stock issuable upon exercise
           of this Warrant on the date of delivery of the Notice of
           Exercise.
       A = the current fair market value of one share of Common Stock.
       B = Warrant Price.

     As used herein, current fair market value of the Common Stock shall mean
the numerical average of fair market value per share of Common Stock over a
period of 21 days consisting of the day on which the Notice of Exercise is
received by the Company and the 20 consecutive business days prior to such day.
The fair market value per share of Common Stock for any day shall mean the
average of the closing prices of the Company's Common Stock sold on all
securities exchanges on which the Common Stock may at the time be listed or as
quoted on the Nasdaq system, or, if there have been no sales on any such
exchange or any such quotation on any day, the average of the highest bid and
lowest asked prices on all such exchanges or such Nasdaq system at the end of
such day, or, if on any day the Common Stock is not so listed, the average of
the representative bid and asked prices quoted in the Nasdaq system as of 4:00
p.m., New York City time, or, if on any day the Common Stock is not quoted in
the Nasdaq system, the average of the highest bid and lowest asked price on such
day in the domestic over-the-counter market as reported by the National
Quotation Bureau, Incorporated, or any similar successor organization. If at any
time the Common Stock is not listed on any securities exchange or quoted in the
Nasdaq system or the over-the-counter market, the current fair market value of
Common Stock shall be the highest price per share which the Company could obtain
from a willing buyer (not a current employee or director) for shares of Common
Stock sold by the

                                      -2-

<PAGE>

Company, from authorized but unissued shares, as determined in good faith by the
Board of Directors of the Company. Notwithstanding the foregoing, if the Company
shall engage in an Acquisition Transaction, as defined below, the current fair
market value of the Common Stock shall be determined with reference to the value
ascribed to the Company by the terms of the Acquisition Transaction. An
"Acquisition Transaction" is (i) the closing of the sale of all or substantially
all of the assets of the Company or (ii) a consolidation or merger or other
business combination to which more than 50% of the equity ownership of the
Company (calculated on a fully-diluted basis) has been transferred.

          1.2 Delivery of Stock Certificates, etc., on Exercise. As soon as
practicable after the exercise of this Warrant in full and in any event within
10 days thereafter, the Company at its expense will cause to be issued in the
name of and delivered to the holder hereof, or as such holder (upon payment by
such holder of any applicable transfer taxes) may direct, a certificate or
certificates for the number of fully paid and nonassessable shares of Common
Stock to which such holder shall be entitled on such exercise.

          1.3 Expiration. This Warrant will expire and be of no further force or
effect at 5 p.m. on the date five (5) years from the date hereof.

     2. Adjustments for Certain Events.

          2.1 Stock Splits, etc. In case the Company shall at any time subdivide
its outstanding shares of Common Stock into a greater number of shares, the
Warrant Price in effect immediately prior to such subdivision shall be
proportionately reduced, and the number of shares of Common Stock issuable upon
exercise of this Warrant shall be proportionately increased; and conversely, in
case the outstanding shares of Common Stock of the Company shall be combined
into a smaller number of shares, the Warrant Price in effect immediately prior
to such combination shall be proportionately increased and the number of shares
of Common Stock issuable upon exercise of this Warrant shall be proportionately
reduced.

          2.2 Adjustments for Capital Reorganization or Reclassification. If any
capital reorganization or reclassification of the capital stock of the Company
shall be effected, then, as a condition of such capital reorganization or
reclassification, lawful and adequate provision shall be made whereby the holder
hereof shall thereafter have the right to purchase and receive upon the basis
and upon the terms and conditions specified in this Warrant, in lieu of shares
of Common Stock of the Company immediately theretofore purchasable and
receivable upon the exercise of the rights represented hereby, those shares of
stock, securities or assets which would have been issued or payable with respect
to or in exchange for the Common Stock issuable upon exercise of this Warrant
had this Warrant been exercised immediately prior to the record date (or the
effective date, as the case may be) for such capital reorganization or
reclassification.

                                      -3-

<PAGE>

          2.3 Acquisition Transaction. The Company shall provide to the holder
of this Warrant written notice not less than thirty (30) business days prior to
the anticipated closing of an Acquisition Transaction of the anticipated closing
of such transaction and a brief summary of the business terms thereof. The
holder of this Warrant will in such case be entitled to exercise this Warrant,
effective immediately prior to the closing of the Acquisition Transaction
(subject to the completion of such closing), as provided in Section 1.1 hereof
by delivery of an executed Notice of Exercise and payment of the exercise price
not less than five (5) days prior to such closing. In the event the closing of
an Acquisition Transaction does not occur for any reason, such Notice of
Exercise will be of no force or effect.

          2.4 Notice of Adjustments. Upon any adjustment of the Warrant Price,
the Company shall give written notice thereof, by first class mail, postage
prepaid, addressed to the holder of this Warrant at its address registered on
the books of the Company, which notice shall state the Warrant Price resulting
from such adjustment and the increased or decreased number of shares purchasable
at such price upon the exercise of this Warrant, setting forth in reasonable
detail the method of calculation and the facts upon which such calculation is
based.

     3. Liquidating Dividends. If the Company pays a dividend or makes a
distribution on the Common Stock payable otherwise than in cash out of earnings
or earned surplus (determined in accordance with generally accepted accounting
principles) except for a stock dividend payable in shares of Common Stock (a
"Liquidating Dividend"), then the Company will pay or distribute to the holder
of this Warrant, upon the exercise hereof, in addition to the Common Stock
purchased upon such exercise, the Liquidating Dividend which would have been
paid to such holder if it had been the owner of record of such shares of Common
Stock immediately prior to the date on which a record is taken for such
Liquidating Dividend or, if no record is taken, the date as of which the record
holders of Common Stock entitled to such dividends or distribution are to be
determined.

     4. Notice of Liquidation, etc. In the event of any voluntary or involuntary
dissolution, liquidation or winding-up of the Company, the Company not less than
ten (10) days prior to the occurrence of such event will give to the holder of
this Warrant written notice of (i) the date on which any such dissolution,
liquidation or winding-up is to take place, (ii) the amount and character of
assets, including any stock or other securities, proposed to be issued or
granted and (iii) the persons or class of persons to whom such proposed issue or
grant is to be made.

     5. Lock-up. The holder of this Warrant agrees not to sell or otherwise
transfer any shares of Common Stock issued or issuable upon exercise of this
Warrant for a period of up to 180 days following the closing of the Company's
initial public offering, provided the underwriters of the offering have
requested that directors, executive officers and other stockholders of the
Company agree not to sell or transfer shares of Common Stock during such period.

                                      -4-

<PAGE>

     6. Reservation of Stock, etc., Issuable on Exercise of Warrants. The
Company will at all times reserve and keep available, solely for issuance and
delivery on the exercise of the Warrant, all shares of Common Stock from time to
time issuable on the exercise of the Warrant.

     7. Voting Rights. This Warrant shall not entitle the holder hereof to
voting rights or any other rights whatsoever as a stockholder of the Company or,
except as set forth in Section 4 above, to any notice of meetings of
stockholders or any other proceedings of the Company.

     8. Exchange of Warrant. Subject to compliance with applicable securities
laws, this Warrant is exchangeable, upon the surrender hereof at the principal
office of the Company, for new Warrants of like tenor representing in the
aggregate the right to subscribe for and purchase the number of shares of Common
Stock which may be subscribed for and purchased hereunder, each of such new
Warrants to represent the right to subscribe for and purchase such number of
shares of Common Stock as shall be designated by such holder hereof at the time
of such surrender.

     9. Transferability. Subject to compliance with applicable securities laws,
this Warrant and all rights hereunder are transferable at the principal office
of the Company by the holder hereof in person or by duly authorized attorney,
upon surrender of this Warrant properly endorsed, together with a written
assignment of this Warrant duly executed by the holder hereof or its duly
authorized attorney. Each taker and holder of this Warrant, by taking or holding
the same, consents and agrees that this Warrant, when endorsed in blank, shall
be deemed negotiable, and that the holder hereof, when this Warrant shall have
been so endorsed, may be treated by the Company and all other persons dealing
with this Warrant as the absolute owner hereof for any purpose and as the person
entitled to exercise the rights represented by this Warrant, or to the transfer
hereof on the books of the Company, any notice to the contrary notwithstanding;
but until such transfer on such books, the Company may treat the holder hereof
as the owner for all purposes.

     10. Miscellaneous. The provisions of this Warrant may be amended or waived
only by an instrument in writing signed by the party against which enforcement
of such amendment or waiver is sought. This Warrant shall be construed and
enforced in accordance with and governed by the laws of the State of Delaware.
The headings in this Warrant are for purposes of reference only, and shall not
limit or otherwise affect any of the terms hereof. This Warrant is being
executed as an instrument under seal. The invalidity or unenforceability of
any provision hereof shall in no way affect the validity or enforceability
of any other provision.

                                      -5-

<PAGE>

     IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by an
officer thereunto duly authorized as of          , 1998.
                                        --------

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

Attest:

--------------------------------
Name:
Title:

                                      -6-

<PAGE>

                               NOTICE OF EXERCISE

                               (To be Executed by
                              the Registered Holder
                        in Order to Exercise the Warrant)

     The undersigned hereby irrevocably elects to exercise the right to purchase
                               (__________) shares of Common Stock, $.01 par
------------------------------
value, of Spectra Science Corporation, covered by Warrant No. W-[_] according to
the conditions thereof and herewith makes payment of the Warrant Price of such
shares in full.

     Specify method of exercise by check mark:

1.   Such payment is hereby made in the amount of $__________ by wire transfer
     or by certified or bank check.

2.   The holder elects to receive shares for the value (as determined pursuant
     to Section 1.1 of the Warrant) of the Warrant.

                                       Printed Name
                                       of Warrant Holder:
                                                          ----------------------

                                       Signature:
                                                  ------------------------------

                                       Title (if signing
                                       on behalf of a
                                       Warrant Holder:
                                                       -------------------------

                                       Address:
                                                --------------------------------

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

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

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

                                      -7-

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00043-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00043-of-00352.parquet"}]]