<PAGE>   1

                                                                   Exhibit 10.2


                                          TENANT: MOLTEN METAL TECHNOLOGY, INC.


                                    LEASE OF

                             400-1 TOTTEN POND ROAD

                             WALTHAM, MASSACHUSETTS

                                TABLE OF CONTENTS



      ARTICLE 1
            BASIC LEASE PROVISIONS.........................................  1

      ARTICLE 2
            PREMISES AND APPURTENANT RIGHTS................................  3

      ARTICLE 3
            BASIC RENT; LANDLORD'S USE OF SPACE............................  4

      ARTICLE 4
            COMMENCEMENT AND CONDITION.....................................  5

      ARTICLE 5
            USE OF PREMISES................................................  9

      ARTICLE 6
            ASSIGNMENT AND SUBLETTING...................................... 11

      ARTICLE 7
            RESPONSIBILITY FOR REPAIRS AND CONDITION OF PREMISES;
            SERVICES TO BE FURNISHED BY LANDLORD........................... 14

      ARTICLE 8
            REAL ESTATE TAXES.............................................. 17

      ARTICLE 9
            OPERATING AND UTILITY EXPENSES................................. 19

      ARTICLE 10
            INDEMNITY AND PUBLIC LIABILITY INSURANCE....................... 21

      ARTICLE 11
            LANDLORD'S ACCESS TO PREMISES.................................. 22

      ARTICLE 12



                                        i


<PAGE>   2



            FIRE, EMINENT DOMAIN, ETC...................................... 22

      ARTICLE 13
            DEFAULT........................................................ 24

      ARTICLE 14
            MISCELLANEOUS PROVISIONS....................................... 29
                  14.1   EXTRA HAZARDOUS USE
                         -------------------
                  14.2   WAIVER
                         ------
                  14.3   COVENANT OF QUIET ENJOYMENT 
                         --------------------------- 
                  14.4   LIMITATION OF LIABILITY
                         -----------------------
                  14.5   NOTICE TO MORTGAGEE OR GROUND LESSOR 
                         ------------------------------------
                  14.6   ASSIGNMENT OF RENTS AND TRANSFER OF TITLE 
                         -----------------------------------------
                  14.7   RULES AND REGULATIONS 
                         ---------------------
                  14.8   ADDITIONAL CHARGES 
                         ------------------
                  14.9   INVALIDITY OF PARTICULAR PROVISIONS
                         -----------------------------------  
                  14.10  PROVISIONS BINDING, ETC 
                         -----------------------
                  14.11  RECORDING 
                         ---------
                  14.12  NOTICES
                         -------
                  14.13  WHEN LEASE BECOMES BINDING 
                         --------------------------  
                  14.14  PARAGRAPH HEADINGS AND INTERPRETATION OF SECTIONS 
                         -------------------------------------------------
                  14.15  RIGHTS OF MORTGAGEE OR GROUND LESSOR 
                         ------------------------------------
                  14.16  STATUS REPORT 
                         -------------
                  14.17  SECURITY DEPOSIT 
                         ----------------
                  14.18  REMEDYING DEFAULTS 
                         ------------------
                  14.19  HOLDING OVER 
                         ------------
                  14.20  WAIVER OF SUBROGATION 
                         --------------------- 
                  14.21  SURRENDER OF PREMISES
                         ---------------------  
                  14.22  BROKERAGE 
                         ---------
                  14.23  GOVERNING LAW
                         ------------- 

      ARTICLE 15
            OPTION TO EXTEND............................................... 37

      ARTICLE 16
            FAIR MARKET RENTAL VALUE....................................... 38

      EXHIBIT OC

      EXHIBIT RR

      EXHIBIT IR

      EXHIBIT CL

      EXHIBIT PL

      EXHIBIT SNDA






                                       ii

<PAGE>   3



      EXHIBIT LOC

      EXHIBIT BB

      EXHIBIT TS

      EXHIBIT CAF






                                       iii
<PAGE>   4


                                    L E A S E
                                    ---------


      THIS INSTRUMENT IS A LEASE, dated as of September 16, 1996, in which the
Landlord and the Tenant are the parties hereinafter named, and which relates to
space in the building (the "Building") located at 400-1 Totten Pond Road,
Waltham, Massachusetts. The parties to this instrument hereby agree with each
other as follows:


                                    ARTICLE 1
                                    ---------

                             BASIC LEASE PROVISIONS
                             ---------------------- 

1.1     INTRODUCTION. The following set forth basic data and, where 
        appropriate, constitute definitions of the terms hereinafter listed.

1.2     BASIC DATA.
        -----------

        Landlord: 400/460 Totten Pond Road Limited Partnership, a Delaware 
        limited partnership.

        Landlord's Original Address: c/o Leggat McCall Properties, L.P., 10 
        Post Office Square, Boston, MA 02109.

        Tenant: MOLTEN METAL TECHNOLOGY, INC., a Delaware corporation.

        Tenant's Original Address: 400-2 Totten Pond Road, Waltham,
        Massachusetts.

        Guarantor: None.

        Basic Rent: (i) For the period commencing on the Commencement Date and
expiring on the day immediately preceding the sixth anniversary of the
Commencement Date, $1,656,226.00 ($22.00 per square foot of Premises Rentable
Area) per annum, (ii) for the remainder of the Initial Term, $1,731,509.00
($23.00 per square foot of Premises Rentable Area) per annum, as all of the same
may be adjusted and/or abated pursuant to Sections 4.2 and .

        Premises Rentable Area: Agreed to be 75,283 square feet.

        Permitted Uses: Executive or professional offices, subject to the 
provisions of Section 5.1(a).

        Escalation Factor: With respect to (i) Park Costs (as defined in Exhibit
OC), 27%, (ii) 400 Costs, 50%, and (iii) Building Costs, 100%.

        Initial Term: The period commencing on the Commencement Date and
expiring at the close of the day immediately preceding the seventh anniversary
of the Commencement Date, as determined in accordance with Section 4.2, except
that if the Commencement Date shall be other than the first day of a calendar
month, the expiration of the Initial Term shall be at the close of the day on
the last day of the calendar month on which such anniversary shall fall,
provided further that, if as a result of any construction delay, as described




                                        1

<PAGE>   5



in Section 4.2, Tenant is granted any period of "free rent," then the Initial
Term shall be extended until the last day of the calendar month in which the
last day of such free rent period occurs.

        Security Deposit: $414,056.50, subject to the provisions of Section 
14.17.

        Base Operating Expenses: The actual Operating Expenses incurred for the
calendar year ending December 31, 1997, exclusive of the cost of electricity and
all other utilities provided to the Building and the surrounding areas of the
Property, to be paid for separately by Tenant pursuant to Section 7.5; PROVIDED
THAT, if during any portion of the calendar year ending December 31, 1997, less
than all of the TPR Properties are occupied by tenants or, if Landlord was not
supplying all tenants with the services being supplied to Tenant hereunder, then
the Operating Expenses actually incurred shall be reasonably extrapolated by
Landlord on an item-by-item basis to the reasonable Operating Expenses that
would have been incurred if the TPR Properties were fully occupied and such
services were being supplied to all tenants, and such extrapolated Operating
Expenses shall, for all purposes hereof, be deemed to be the Base Operating
Expenses hereunder. If and when Landlord discontinues providing the traffic
control services referred to in Section 7.4(b)(vi), Base Operating Expenses
shall thereafter be reduced by the amount theretofore included in Base Operating
Expenses for such services.

        Base Taxes: Base Taxes shall be the product of (i) Taxes actually
assessed with respect to the Property for the fiscal year ending June 30, 1999
(as the same may be reduced by the amount of any abatement), multiplied by (ii)
0.96, but in no event shall Base Taxes be less than Taxes actually assessed with
respect to the Property for the fiscal year ending June 30, 1998 (as the same
may be reduced by the amount of any abatement).

        Broker: Fallon, Hines & O'Connor.


1.3     ADDITIONAL DEFINITIONS.
        -----------------------

        Agent: Leggat McCall Properties Management, L.P., 460 Totten Pond Road, 
Waltham, MA, Attn: Property Manager, or such other person or entity from time to
time designated by Landlord.

        Business Days: All days except Saturday, Sunday, New Year's Day, Martin
Luther King Day, President's Day, Memorial Day, Independence Day, Labor Day,
Columbus Day, Veterans' Day, Thanksgiving Day, Christmas Day (and the following
day when any such day occurs on Sunday).

        Commencement Date: As defined in Section 4.1.

        Construction Deadline: As defined in Section 4.2.

        Default of Tenant: As defined in Section 13.1.

        Escalation Charges: The amounts prescribed in Sections 8.1 and 9.2.

        Extended Term: As defined in Section 15.1.

        Fair Market Rental Value: As determined in accordance with Section 17.1.




                                        2

<PAGE>   6


        Force Majeure: Collectively and individually, strike or other labor
trouble, fire or other casualty, governmental preemption of priorities or other
controls in connection with a national or other public emergency or shortages of
fuel, supplies or labor resulting therefrom, or any other cause, whether similar
or dissimilar, beyond Landlord's reasonable control.

        Initial Public Liability Insurance:  $2,000,000 per occurrence/
$10,000,000 aggregate (combined single limit) for property damage, bodily injury
or death.

        Landlord's Loan: As defined in Section 4.2.

        Landlord's Work: As defined in Section 4.2.

        Operating Expenses:  As determined in accordance with Section 9.1 and 
EXHIBIT OC.

        Operating Year: As defined in Section 9.1.

        Premises: The entire ground, second, third and fourth floors of the 
Building, except as provided otherwise in Section 2.2.

        Property: The Building and the land parcel on which it is located 
(including adjacent sidewalks).

        Proposed Space: As defined in Section 18.1.

        Substantial Completion Date: As defined in Section 4.2.

        Target Date: As defined in Section 4.2.

        Tax Year: As defined in Section 8.1.

        Taxes: As determined in accordance with Section 8.1.

        Tenant's Removable Property: As defined in Section 5.2.

        Term of this Lease: The Initial Term and any extension thereof in
accordance with the provisions hereof.

        TPR Properties: Properties owned by Landlord or an affiliate of Landlord
and currently known as 400-1, 400-2 and 460 Totten Pond Road, Waltham,
Massachusetts.


                                    ARTICLE 2
                                    ---------

                         PREMISES AND APPURTENANT RIGHTS
                         -------------------------------

2.1     LEASE OF PREMISES. Landlord hereby demises and leases to Tenant for the 
        Term of this Lease and upon the terms and conditions hereinafter set
        forth, and Tenant hereby accepts from Landlord, the Premises.





                                        3


<PAGE>   7



2.2     APPURTENANT RIGHTS AND RESERVATIONS. (a) Tenant shall have, as
        appurtenant to the Premises, the non-exclusive right to use, and permit
        its invitees to use in common with others, public or common walkways
        necessary for access to the Building; but such rights shall always be
        subject to reasonable rules and regulations from time to time
        established by Landlord pursuant to Section 14.7 and to the right of 
        Landlord to designate and change from time to time areas and facilities
        so to be used (provided that no such change shall have the effect of 
        materially interfering with or impairing Tenant's rights under this 
        Lease, including without limitation free access to the Building and use
        and enjoyment of the Premises.

        (b) Excepted and excluded from the Premises are the structural elements
        of the Building, including without limitation the roof, exterior walls,
        foundations and exterior windows (except the inner surface thereof), and
        any space in the Premises used for shafts, stacks, pipes, conduits, fan
        rooms, ducts, electric or other utilities, sinks or other Building
        facilities, but the exterior entry doors (and related glass and finish
        work), interior partitions and doors, hung ceilings and lobby areas are
        a part thereof. Landlord shall have the right, in connection with
        Landlord's maintenance and repair obligations, to place in the Premises
        (but in such manner as to reduce to a minimum interference with Tenant's
        use of the Premises) interior storm windows, utility lines, equipment,
        stacks, pipes, conduits, ducts and the like. In addition, but subject to
        Tenant's reasonable security restrictions set forth in Exhibit TS,
        Landlord and its agents, employees and contractors shall have the right
        to pass through that portion of the Premises located on the ground floor
        of the Building to gain access to the first floor mechanical and
        electrical rooms. In the event that Tenant shall install any hung
        ceilings or walls in the Premises, Tenant shall install and maintain, as
        Landlord may require, proper access panels therein to afford access to
        any facilities above the ceiling or within or behind the walls.

        (c) Tenant shall also have the right (subject to reasonable rules and
        regulations from time to time established by Landlord) to use, on an
        non-exclusive, unreserved basis, up to four (4) parking spaces located
        on the Property for each 1,000 square feet of Premises Rentable Area, or
        301 spaces. Landlord shall not be responsible for policing the parking
        areas or for restricting access thereto by parties other than tenants of
        Landlord's buildings. Such spaces shall be used for private automobiles,
        only and not for delivery trucks.


                                    ARTICLE 3
                                    ---------

                       BASIC RENT; LANDLORD'S USE OF SPACE
                       -----------------------------------

3.1     PAYMENT. (a) Tenant agrees to pay to Landlord, or as directed by
        Landlord, commencing on the Commencement Date without offset, abatement
        (except as provided in Section 12.1), deduction or demand, the Basic 
        Rent. Such Basic Rent shall be payable in equal monthly installments, in
        advance, on the first day of each and every calendar month during the
        Term of this Lease, to Landlord at P.O. Box 3737, Boston, MA 02241-3737,
        or at such other place as Landlord shall from time to time designate by
        notice, in lawful money of the United States. In the event that, twice
        during any twelve-month period, any installment of Basic Rent is not
        paid within five (5) Business Days after the due date, then with each
        succeeding late payment (until Tenant shall have made eleven consecutive
        timely payments), Tenant shall pay, in an addition to any charges under
        Section 14.18, at Landlord's request an administrative fee equal to 5% 
        of the overdue payment, which Landlord and Tenant expressly agree shall
        not be deemed a penalty. Landlord and Tenant agree that



                                        4


<PAGE>   8


        all amounts due from Tenant under or in respect of this Lease, whether
        labelled Basic Rent, Escalation Charges, additional charges or
        otherwise, shall be considered as rental reserved under this Lease for
        all purposes, including without limitation regulations promulgated
        pursuant to the Bankruptcy Code, and including further without
        limitation Section 502(b) thereof.

        (b) Basic Rent for any partial month shall be pro-rated on a daily
        basis, and if the first day on which Tenant must pay Basic Rent shall be
        other than the first day of a calendar month, the first payment which
        Tenant shall make to Landlord shall be equal to a proportionate part of
        the monthly installment of Basic Rent for the partial month from the
        first day on which Tenant must pay Basic Rent to the last day of the
        month in which such day occurs.


                                    ARTICLE 4
                                    ---------
                           COMMENCEMENT AND CONDITION
                           --------------------------
 

4.1     COMMENCEMENT DATE.  The Commencement Date shall be the last to occur of:
        ------------------

        (a) February 1, 1997, or

        (b) the eighth day following the Substantial Completion Date of any
            portion of the Premises, as defined in Section 4.2(c).

        Notwithstanding the foregoing, but subject to paragraph (d) below, if
        Tenant's personnel shall occupy all or any part of the Premises for the
        conduct of its business prior to the Commencement Date as determined
        pursuant to the preceding sentence, such date of occupancy shall, for
        all purposes of this Lease, be the Commencement Date. Promptly upon the
        occurrence of the Commencement Date and the expiration of any free rent
        periods described in Sections 4.2(e) and 4.5, Landlord and Tenant shall
        enter into a letter agreement substantially in the form annexed hereto
        as EXHIBIT CL, but the failure by either party to execute such a letter
        shall have no effect on the Commencement Date, as hereinabove
        determined.

4.2     PREPARATION OF THE PREMISES. (a) Tenant is currently having full
        construction drawings and plans (the "Plans") for the layout of the
        Premises prepared, which Plans shall conform to the requirements set
        forth in part III of EXHIBIT RR, and be submitted to Landlord for its
        approval on or before October 1, 1996 (the "Plan Submission Date"),
        which approval shall not be unreasonably withheld or delayed. Failure by
        Landlord to disapprove any submission of the Plans within ten (10)
        Business Days after submission shall constitute approval thereof. Any
        disapproval shall be accompanied by a reasonably specific statement of
        reasons therefor. Promptly upon receipt of any such disapproval, Tenant
        shall, within ten (10) Business Days, revise the Plans to address
        Landlord's reasons for disapproval and resubmit the same to Landlord. At
        such time as the Plans are completed and approved by Landlord, Landlord
        and Tenant shall sign a letter agreement substantially in the form of
        EXHIBIT PL, identifying the Plans and reciting such approval, and a copy
        of such letter shall be appended to each counterpart of this Lease.

        (b) Promptly after (i) approval of the Plans, (ii) issuance by the City
        of Waltham of a building permit and any other licenses or approvals
        necessary under applicable law for Landlord's Work to

                                   

                                        5

<PAGE>   9


        commence, and (iii) payment by Tenant of any excess cost referred to
        below (and execution of a work letter if requested by Landlord),
        Landlord shall exercise all reasonable efforts to substantially complete
        the work ("Landlord's Work") specified therein on or before January 24,
        1997 (the "Target Date," as it may be extended pursuant to Section 4.4).
        Tenant shall have no claim against Landlord for failure to complete such
        Work on or before the Target Date, except the right to the "free rent"
        period, and the right to terminate this Lease, both as hereinafter
        described. Upon completion and approval of the Plans, Landlord shall
        enter into a so-called "Cost-Plus" construction contract with Landlord's
        contractor, which contract shall also provide for a guaranteed maximum
        price (the "GMP"). The construction contract shall provide that the
        contractor shall bear any financial responsibility for excess of the
        actual cost of performing Landlord's Work over and above the GMP, except
        in the event of change orders. To the extent that the GMP set forth in
        the construction contract exceeds an amount ("Landlord's Contribution")
        equal to $1,693,867.50 ($22.50 per square foot of Premises Rentable
        Area), Tenant shall (subject to the provisions of paragraph (c) below)
        pay such excess to Landlord within 5 days after the date Tenant's Plans
        are approved and the GMP is established (or such later time as Landlord
        advises Tenant of the amount of such excess). Tenant shall, if requested
        by Landlord, execute a work letter confirming such excess costs prior to
        the time Landlord shall be required to commence work. In the event that
        the actual cost to Landlord of completing Landlord's Work exceeds
        Landlord's Contribution, but is less than the GMP, then Landlord shall
        refund such difference within fifteen (15) days after Landlord shall
        advise Tenant of such actual cost. In the event that the actual cost to
        Landlord of completing Landlord's Work is less than Landlord's
        Contribution, then Landlord shall credit against payments of Basic Rent
        subsequently coming due the amount by which Landlord's Contribution
        exceeds such cost. In addition, if after approval of the Plans, Tenant
        shall request any changes in Landlord's Work, which changes will result
        in an increase in the GMP, as a condition to Landlord's obligation to
        agree to such change, Tenant shall pay to Landlord any such increase in
        the GMP, such payment to be made within five (5) days after Landlord
        advises Tenant of the amount of such increase. For purposes of computing
        the cost of performing Landlord's Work: (i) up to $376,415.00 ($5.00 per
        square foot of Premises Rentable Area) of the total Landlord's
        Contribution may be applied to so-called "soft" costs, including
        architectural and engineering services, moving into the Premises,
        installing cabling and other telecommunication equipment, but excluding
        Tenant's furniture, fixtures and equipment; and (ii) construction
        management fees paid by Landlord shall not be included in the cost of
        such Work. Landlord's Work does not include the work ("Base Building
        Work") currently being undertaken by Landlord, which is identified on
        EXHIBIT BB hereto, and the cost of performing the Base Building Work
        shall not be deemed to be included in the cost of performing Landlord's
        Work. If and to the extent that Tenant may elect to have Landlord
        perform Landlord's Work in less than all of the Premises, for purposes
        of this Article 4, wherever amounts are computed on the basis of "per
        square foot of Premises Rentable Area," the same shall refer to the
        number of square feet of Premises Rentable Area as to which Landlord's
        Work is actually being performed.

        (c) The Premises shall be deemed ready for occupancy on the first day
        (the "Substantial Completion Date") as of which: (i) Landlord's Work has
        been completed except for items of work (and, if applicable, adjustment
        of equipment and fixtures) which can be completed after occupancy has
        been taken without causing undue interference with Tenant's use of the
        Premises (i.e. so-called "punch list" items); (ii) a certificate of use
        and occupancy (which may be temporary) has been issued therefor; and
        (iii) Tenant has been given notice thereof ("Substantial Completion").
        Landlord shall expeditiously (but in any event within 60 days) complete
        all "punch list" items and Tenant shall afford Landlord access to the
        Premises for such purposes. Tenant acknowledges that, given the scope of
        Landlord's Work, it is possible that Substantial Completion may occur as
        to certain

                                      6


<PAGE>   10


        portions of the Building before all of Landlord's Work is substantially
        complete. If (i) Tenant shall desire to occupy a portion of the Premises
        prior to Substantial Completion of all of Landlord's Work, and (ii)
        Landlord, in its sole and absolute discretion, determines that partial
        occupancy by Tenant of such portions of the Building as shall have been
        substantially complete will not interfere with or delay the remainder of
        Landlord's Work, Landlord may give Tenant notice thereof and, subject to
        Section 4.1(a), Tenant may occupy that portion of the Premises as to
        which Substantial Completion has occurred, and the Substantial
        Completion Date shall be deemed to have occurred as to such portion, and
        all payments of Basic Rent, Escalation Charges and the like shall be
        prorated according to the amount of space as to which Substantial
        Completion shall have been achieved.

        (d) If the Substantial Completion Date has not occurred on or before the
        thirtieth (30th) day after the Target Date (as so extended), then for
        each day after such 30th day that Substantial Completion is not
        achieved, Tenant shall not be required to pay Basic Rent or Escalation
        Charges for one (1) day after the Commencement Date. Further, if the
        Substantial Completion Date has not occurred on or before the sixtieth
        (60th) day after the Target Date (as so extended), then for each day
        after such 60th day that Substantial Completion is not achieved, Tenant
        shall not be required to pay Basic Rent or Escalation Charges for one
        and one-half (1 1/2) days after the Commencement Date. If the
        Substantial Completion Date has not occurred on or before the ninetieth
        (90th) day (the "Construction Deadline") after the Target Date (as so
        extended), Tenant shall have the right to terminate this Lease by giving
        notice to Landlord, not later than thirty (30) days after the
        Construction Deadline, of Tenant's desire so to do; and this Lease shall
        cease and come to an end without further liability or obligation on the
        part of either party thirty (30) days after the giving of such notice,
        unless, within such additional 30-day period, Landlord substantially
        completes Landlord's Work; and such rights of free rent and termination
        shall be Tenant's sole and exclusive remedies at law or in equity for
        Landlord's failure so to complete such Work within such time.

4.3     CONCLUSIVENESS OF LANDLORD'S PERFORMANCE. Except to the extent to which
        Tenant shall have given Landlord notice, not later than the end of the
        fourth full calendar month of the Term of this Lease next beginning
        after the Commencement Date, of respects in which Landlord has not
        performed Landlord's Work, Tenant shall have no claim that Landlord has
        failed to perform any of Landlord's Work. Except for Landlord's Work and
        the Base Building Work, and except as expressly provided herein, the
        Premises are being leased in their condition AS IS WITHOUT
        REPRESENTATION OR WARRANTY by Landlord. Tenant acknowledges that it has
        inspected the Premises and, except for Landlord's Work and the Base
        Building Work, has found the same satisfactory. Notwithstanding the
        foregoing, Landlord hereby represents and warrants to Tenant that: (i)
        Landlord's Work and the Base Building Work will be undertaken in
        accordance with all applicable laws, codes and ordinances, including
        without limitation the Americans With Disabilities Act of 1990, and (ii)
        Landlord has not received from any governmental agency having
        jurisdiction any written notice to the effect that the Premises are in
        violation of any applicable law, code or ordinance, which violation
        remains outstanding as of the date hereof. To the extent that Tenant
        will be responsible for maintenance and/or repair of any item of work
        included in Landlord's Work or the Base Building Work, then Landlord
        shall use reasonable efforts to obtain from Landlord's contractor a
        warranty for the benefit of Tenant covering such items.

4.4     TENANT'S DELAYS.  (a)  If a delay shall occur in the Substantial 
        Completion Date as the result of:


                                        7


<PAGE>   11


        (i)       any written request by Tenant that Landlord delay in the 
                  commencement or completion of Landlord's Work for any reason;

        (ii)      failure by Tenant to (x) submit the Plans on or before the
                  Plan Submission Date, and revise the same to satisfy
                  Landlord's reasonable objections within the time periods set
                  forth above, or (y) enter into a work letter if so requested
                  by Landlord, or (z) any change by Tenant in any of the Plans
                  after approval or deemed approval thereof by Landlord;

        (iii)     any other act or omission of Tenant or its officers, agents,
                  servants or contractors, provided that no act or omission
                  shall be deemed a cause for delay except to the extent that
                  Landlord shall have given Tenant written notice thereof within
                  two (2) Business Days after Landlord becomes aware of the
                  delay;

        (iv)      any special requirement of the Plans not in accordance with
                  Landlord's building standards, which Landlord shall have
                  identified prior to commencement of Landlord's Work as a
                  potential cause for delay; or

        (v)       any reasonably necessary displacement of any of Landlord's
                  Work from its place in Landlord's construction schedule
                  resulting from any of the causes for delay referred to in
                  clauses (i), (ii), (iii) or (iv) of this paragraph and the
                  fitting of such Work back into such schedule;

        AND, as a result of such delay, Substantial Completion does not occur
        before February 24, 1997, then Tenant shall, commencing on February 24,
        1997, pay to Landlord for each day of such delay the amount of Basic
        Rent, Escalation Charges and other charges that would have been payable
        hereunder had the Tenant's obligation to pay Basic Rent commenced on
        February 24, 1997 (without regard to any "free rent" period).

        (b) If a delay in the Substantial Completion Date, or if any substantial
        portion of such delay, is the result of Force Majeure, and such delay
        would not have occurred but for a delay described in paragraph (a), such
        delay shall be deemed added to the delay described in that paragraph.

        (c) The delays referred to in paragraphs (a) and (b) are herein 
        referred to collectively and individually as "Tenant's Delay."

        (d) If, as a result of Tenant's Delay(s), the Substantial Completion
        Date is delayed in the aggregate for more than one hundred twenty (120)
        days, Landlord may (but shall not be required to) at any time thereafter
        terminate this Lease by giving written notice of such termination to
        Tenant and thereupon this Lease shall terminate without further
        liability or obligation on the part of either party, except that Tenant
        shall pay to Landlord the cost theretofore incurred by Landlord in
        performing Landlord's Work, plus an amount equal to Landlord's
        out-of-pocket expenses incurred in connection with this Lease,
        including, without limitation, brokerage and legal fees, together with
        any amount required to be paid pursuant to paragraph (a) through the
        effective termination date.

        (e) The Target Date shall automatically be extended for the period of
        any delays caused by Tenant's Delay(s) or Force Majeure.


                                        8


<PAGE>   12



                                    ARTICLE 5
                                    ---------

                                 USE OF PREMISES
                                 ---------------
  

5.1     PERMITTED USE. (a) Tenant agrees that the Premises shall be used and
        occupied by Tenant only for Permitted Uses specifically excluding,
        without limitation, use for medical, dental, governmental, utility
        company or employment agency offices, provided that use of the Premises
        for offices for a governmental agency with whom Tenant has an ongoing
        relationship in the course of the conduct of Tenant's business shall not
        be prohibited hereby.

        (b)  Tenant agrees to conform to the following provisions during the 
        Term of this Lease:

            (i) Tenant shall cause all freight to be delivered to or removed
            from the Premises in accordance with reasonable rules and
            regulations established by Landlord therefor;

            (ii) Tenant will not place on the exterior of the Premises
            (including both interior and exterior surfaces of doors and interior
            surfaces of windows) or on any part of the Building outside the
            Premises, any signs, symbol, advertisement or the like visible to
            public view outside of the Premises. Notwithstanding the foregoing,
            Landlord agrees that, so long as Tenant actually occupies at least
            fifty-one percent (51%) of Premises Rentable Area, Tenant shall have
            the right to place one sign, bearing Tenant's name and logo, on the
            exterior of the Building, provided that (i) Tenant shall comply with
            all applicable laws, regulations and ordinances and shall obtain at
            its expense any necessary permits or approvals, and (ii) Landlord
            shall have first approved detailed plans and specifications
            therefor, which shall show, at a minimum, the size and style of such
            sign, the materials to be used, and the method of affixation. Tenant
            shall remove such sign (and repair any damage arising from such
            sign) upon the request of Landlord at the expiration or earlier
            termination of this Lease, or if Tenant shall cease to occupy at
            least fifty-one percent (51%) of Premises Rentable Area. Landlord
            agrees to construct and maintain, at its sole cost and expense, a
            tenant directory at the driveway entrance to the business park of
            which the Building is a part, on which will be placed Tenant's name
            and the location of the Premises;

            (iii) Tenant shall not perform any act or carry on any practice
            which may injure the Premises, or any other part of the Building, or
            cause any offensive odors or loud noise or constitute a nuisance or
            a menace to any other tenant or tenants or other persons; and

            (iv) Tenant shall, in its use of the Premises, comply with the
            requirements of all applicable governmental laws, rules and
            regulations, including without limitation the Americans With
            Disabilities Act of 1990.


                                      9


<PAGE>   13


5.2     INSTALLATIONS AND ALTERATIONS BY TENANT. (a) Tenant shall make no
        alterations, additions (including, for the purposes hereof, wall-to-wall
        carpeting), or improvements in or to the Premises (including any
        improvements other than Landlord's Work necessary for Tenant's initial
        occupancy of the Premises) without Landlord's prior written consent,
        which consent shall not be unreasonably withheld or delayed with respect
        to non-structural alterations, additions and improvements that do not
        affect the Building's electrical, plumbing or mechanical systems.
        Notwithstanding the foregoing, Tenant may, without Landlord's prior
        written consent, make non-structural alterations to the Premises which
        do not materially or adversely affect the Building's electrical,
        plumbing or mechanical systems, and which do not involve the expenditure
        of $15,000 or more for any given alteration (or series of related
        alterations), provided that Tenant shall notify Landlord of the same in
        advance, describing in reasonable detail the nature of the work to be
        done and the cost thereof. To the extent that, under applicable laws or
        codes or, consistent with sound and accepted building management and
        construction practices, plans, specifications, drawings or the like
        would be prepared in connection with work such as that being proposed,
        Tenant shall have such plans, specifications or drawings prepared
        (meeting the requirements set forth in the rules and regulations from
        time to time in effect) and approved in advance by Landlord (such
        approval not to be unreasonably withheld or delayed), and any such
        alterations, additions or improvements shall be in accordance with the
        same. In addition, to the extent that any permits or approvals are
        required in connection with such alterations, additions or improvements,
        copies thereof shall be delivered to Landlord in advance of commencement
        of work. Such work shall (i) be performed in a good and workmanlike
        manner and in compliance with all applicable laws, (ii) be made at
        Tenant's sole cost and expense and in such a manner as Landlord may from
        time to time reasonably designate, (iii) be made only in accordance with
        the rules and regulations from time to time in effect with respect
        thereto, and (iv) become part of the Premises and the property of
        Landlord. If any alterations or improvements shall involve the removal
        of fixtures, equipment or other property in the Premises which are not
        Tenant's Removable Property, such fixtures, equipment or property shall
        be promptly replaced by Tenant at its expense with new fixtures,
        equipment or property of like utility and of at least equal quality.

        (b) All articles of personal property and all business fixtures,
        machinery and equipment and furniture owned or installed by Tenant
        solely at its expense in the Premises ("Tenant's Removable Property")
        shall remain the property of Tenant and may be removed by Tenant at any
        time prior to the expiration of this Lease, provided that Tenant, at its
        expense, shall repair any damage to the Building caused by such removal.

        (c) Notice is hereby given that Landlord shall not be liable for any
        labor or materials furnished or to be furnished to Tenant upon credit,
        and that no mechanic's or other lien for any such labor or materials
        shall attach to or affect the reversion or other estate or interest of
        Landlord in and to the Premises. To the maximum extent permitted by law,
        before such time as any contractor commences to perform work on behalf
        of Tenant, such contractor (and any subcontractors) shall furnish a
        written statement acknowledging the provisions set forth in the prior
        clause. Whenever and as often as any mechanic's lien shall have been
        filed against the Property based upon any act or interest of Tenant or
        of anyone claiming through Tenant, Tenant shall forthwith take such
        action by bonding, deposit or payment as will remove or satisfy the
        lien.

        (d) In the course of any work being undertaken by either Landlord or
        Tenant, each party shall use all reasonable efforts to coordinate with
        the other as to possible labor problems of which such party becomes
        aware.

                                      10


<PAGE>   14




                                    ARTICLE 6
                                    ---------

                            ASSIGNMENT AND SUBLETTING
                            -------------------------

                              
6.1     PROHIBITION. (a) Except as expressly permitted in this Article 6, Tenant
        covenants and agrees that whether voluntarily, involuntarily, by
        operation of law or otherwise neither this Lease nor the term and estate
        hereby granted, nor any interest herein or therein, will be assigned,
        mortgaged, pledged, encumbered or otherwise transferred and that neither
        the Premises nor any part thereof will be encumbered in any manner by
        reason of any act or omission on the part of Tenant, or used or occupied
        or permitted to be used or occupied, by anyone other than Tenant, or for
        any use or purpose other than a Permitted Use, or be sublet (which term,
        without limitation, shall include granting of concessions, licenses and
        the like) in whole or in part, or be offered or advertised for
        assignment or subletting. Without limiting the foregoing, any agreement
        pursuant to which: (x) Tenant is relieved from the obligation to pay, or
        a third party agrees to pay on Tenant's behalf, all or any portion of
        Basic Rent, Escalation Charges or other charges due under this Lease;
        and/or (y) a third party undertakes or is granted the right to assign or
        attempt to assign this Lease or sublet or attempt to sublet all or any
        portion of the Premises, shall for all purposes hereof be deemed to be
        an assignment of this Lease and subject to the provisions of this
        Article 6. The provisions of this paragraph (a) shall apply to a
        transfer (by one or more transfers) of a majority of the stock or
        partnership interests or other evidences of ownership of Tenant as if
        such transfer were an assignment of this Lease.

        (b) The provisions of paragraph (a) shall not apply to either:
        transactions with an entity into or with which Tenant is merged or
        consolidated, or to which substantially all of Tenant's assets are
        transferred; or transactions with any entity which controls or is
        controlled by Tenant or is under common control with Tenant; provided
        that in either such event:

            (i) the successor to Tenant has a net worth and working capital,
            computed in accordance with generally accepted accounting principles
            consistently applied, sufficient in Landlord's reasonable judgment
            to assure the future performance by assignee of Tenant's obligations
            under this Lease,

            (ii) proof satisfactory to Landlord of such net worth shall have
            been delivered to Landlord at least 10 days prior to the effective
            date of any such transaction, and

            (iii) the assignee agrees directly with Landlord, by written
            instrument in form reasonably satisfactory to Landlord, to be bound
            by all the obligations of Tenant hereunder including, without
            limitation, the covenant against further assignment and subletting.

        (c) If, in violation of this Article 6, this Lease be assigned, or if
        the Premises or any part thereof be sublet or occupied by anyone other
        than Tenant, Landlord may, at any time and from time to time, collect
        rent and other charges from the assignee, subtenant or occupant, and
        apply the net amount collected to the rent and other charges herein
        reserved, but no such assignment, subletting, occupancy, collection or
        modification of any provisions of this Lease shall be deemed a waiver of
        this covenant, or the acceptance of the assignee, subtenant or occupant
        as a tenant or a release of

                                      11


<PAGE>   15


        Tenant from the further performance of covenants on the part of Tenant
        to be performed hereunder. Any consent by Landlord to a particular
        subletting or occupancy shall not in any way diminish the prohibition
        stated in paragraph (a) of this Section 6.1 or the continuing liability
        of the original named Tenant. No assignment or subletting hereunder
        shall relieve Tenant from its obligations hereunder and Tenant shall
        remain fully and primarily liable therefor. No such assignment,
        subletting, or occupancy shall affect or be contrary to Permitted Uses.
        Any consent by Landlord to a particular assignment, subletting or
        occupancy shall be revocable, and any assignment, subletting or
        occupancy shall be void ab initio, if the same shall fail to require
        that such assignee, subtenant or occupant agree therein to be
        independently bound by and upon all of the covenants, agreements, terms,
        provisions and conditions set forth in this Lease on the part of Tenant
        to be kept and performed.

6.2     CONSENT TO SUBLEASE. Notwithstanding the prohibition set forth in 
        Section 6.1(a), Landlord shall not unreasonably withhold its consent to
        one or more sublettings requested by Tenant, provided further that:

            (i) The business of each proposed subtenant and its use of the
            Premises shall be consistent with the Permitted Uses.

            (ii) Neither the proposed subtenant, nor any person who directly or
            indirectly, controls, is controlled by, or is under common control
            with, the proposed subtenant or any person who controls the proposed
            subtenant, shall be (A) a government (or subdivision or agency
            thereof), except as otherwise provided in Section 5.1, or (B) an
            occupant of any TPR Property;

            (iii) The form of the proposed sublease shall be reasonably
            satisfactory to Landlord and shall comply with the applicable
            provisions of this Article 6;

            (iv) No proposed sublease for which the sublet space shall be
            physically segregated shall cover less than 5,000 square feet of
            Premises Rentable Area; and

            (v) not later than thirty (30) days prior to the proposed
            commencement of such sublease, Landlord shall have received
            information reasonably sufficient to determine compliance with the
            foregoing conditions.

            Moreover, notwithstanding such sublease, Tenant shall in all cases
        remain fully and primarily liable hereunder. Landlord agrees to respond
        with reasonable promptness to any request by Tenant for any consent
        described above.

6.3     EXCESS PAYMENTS. In the event that Tenant shall enter into one or more
        subleases pursuant to Section 6.2, if the rent and other sums (including
        without limitation the fair value of any services provided by such
        subtenant for Tenant) on account of any such sublease exceed the Basic
        Rent and Escalation Charges allocable to that portion of the Premises
        subject to such sublease, plus actual out-of-pocket third party expenses
        reasonably incurred in connection with such sublease (such expenses to
        be pro-rated evenly over the term of such sublease), including without
        limitation reasonable brokerage commissions actually paid to a licensed
        broker, Tenant shall pay to Landlord, as an

                                      12


<PAGE>   16


        additional charge, 50% of such excess, such amount to be paid monthly
        with payments by Tenant of Basic Rent hereunder.

6.4     TERMINATION. Notwithstanding any other provision of this Article VI to
        the contrary, if and at each such time as Tenant shall intend to enter
        into any sublease, which sublease either (i) covers all or substantially
        all of the Premises, or (ii) covers less than all or substantially all
        of the Premises, but covers at least twenty-five percent (25%)of
        Premises Rentable Area, and has a term (including options to extend or
        renew) covering all or substantially all of the remainder of the Term of
        this Lease (excluding any extension options with respect to which Tenant
        shall not then have exercised its options), then Tenant shall give
        Landlord notice of such intent not earlier than sixty (60), and not
        later than thirty (30), days prior to the effective date of such
        proposed sublease, and Landlord may then elect to terminate this Lease
        (if less than all or substantially all of the Premises are covered by
        such sublease, then such termination shall affect only that portion of
        the Premises proposed to be covered by such sublease) by giving notice
        to Tenant of such election not later than fifteen (15) days after
        receipt of Tenant's notice and, upon the giving of such notice by
        Landlord, this Lease shall terminate with respect to such portion thirty
        (30) days after the giving of such notice by Landlord with the same
        force and effect as if such date were the date originally set forth
        herein as the expiration date hereof. If Landlord shall elect to
        terminate this Lease with respect to any portion of the Premises as
        hereinabove provided, then (A) from and after the effective date of such
        termination, the definitions of Basic Rent, Premises, Premises Rentable
        Area and Escalation Factor shall be adjusted to reflect that portion of
        the Premises that remains subject to this Lease after such termination,
        and (B) Tenant shall pay to Landlord, as an additional charge, any costs
        incurred by Landlord in connection with physically separating such
        terminated portion from the remainder of the Premises and complying with
        any laws, regulations and requirements of governmental authorities
        regarding the creation of multi-tenant floors.

6.5     MISCELLANEOUS. (a) Any sublease consented to by Landlord shall be
        expressly subject and subordinate to all of the covenants, agreements,
        terms, provisions and conditions contained in this Lease. Any proposed
        sub-sublease or proposed assignment of a sublease shall be subject to
        the provisions of this Article. Tenant shall reimburse Landlord on
        demand, as an additional charge, for any out-of-pocket costs (including
        reasonable attorneys' fees and expenses) incurred by Landlord in
        connection with any actual or proposed assignment or sublease, whether
        or not consummated, including the costs of making investigations as to
        the acceptability of the proposed assignee or subtenant. Any sublease to
        which Landlord gives its consent shall not be valid or binding on
        Landlord unless and until Tenant and the sublessee execute a consent
        agreement in form and substance reasonably satisfactory to Landlord.

        (b) Notwithstanding any sublease, or any amendments or modifications
        subsequent thereto, Tenant will remain fully liable for the payment of
        Basic Rent, Escalation Charges and other charges and for the performance
        of all other obligations of Tenant contained in this Lease. Any act or
        omission of any subtenant, or of anyone claiming under or through any
        subtenant, that violates any of the obligations of this Lease shall be
        deemed a violation of this Lease by Tenant.

        (c) The consent by Landlord to any sublease shall not relieve Tenant or
        any person claiming through or under Tenant of the obligation to obtain
        the consent of Landlord, pursuant to the provisions of this Article, to
        any subsequent sublease.


                                       13


<PAGE>   17


        (d) With respect to each and every sublease authorized by Landlord under
        the provisions of this Article, it is further agreed that any such
        sublease shall provide that: (i) the term of the sublease must end no
        later than one day before the last day of the Term of this Lease; (ii)
        no sublease shall be valid, and no subtenant shall take possession of
        all or any part of the Premises until a fully executed counterpart of
        such sublease has been delivered to Landlord; (iii) each sublease shall
        provide that it is subject and subordinate to this Lease; (iv) Landlord
        may enforce the provisions of the sublease, including collection of
        rents; (v) in the event of termination of this Lease or reentry or
        repossession of the Premises by Landlord, Landlord may, at its option,
        take over all of the right, title and interest of Tenant, as sublessor,
        under such sublease, and such subtenant shall, at Landlord's option,
        attorn to Landlord but nevertheless Landlord shall not (A) be liable for
        any previous act or omission of Tenant under such sublease; (B) be
        subject to any defense or offset previously accrued in favor of the
        subtenant against Tenant; or (C) be bound by any previous modification
        of such sublease made without Landlord's written consent or by any
        previous prepayment of more than one month's rent.

6.6     ACCEPTANCE OF RENT. If this Lease is assigned, whether or not in
        violation of the provisions of this Lease, Landlord may collect rent
        from the assignee. If all or any part of the Premises are sublet,
        whether or not in violation of this Lease, Landlord may, after default
        by Tenant and expiration of Tenant's time to cure such default, collect
        rent from the subtenant. In either event, Landlord may apply the net
        amount collected to payment of Rents, but no such assignment,
        subletting, or collection shall be deemed a waiver of any of the
        provisions of this Article, an acceptance of the assignee or subtenant
        as a lessee, or a release of Tenant from the performance by Tenant of
        Tenant's obligations under this Lease.


                                    ARTICLE 7
                                    ---------

              RESPONSIBILITY FOR REPAIRS AND CONDITION OF PREMISES;
              -----------------------------------------------------
                      SERVICES TO BE FURNISHED BY LANDLORD
                      ------------------------------------


7.1     LANDLORD REPAIRS. (a) Except as otherwise provided in this Lease,
        Landlord agrees, at its sole cost and expense (subject to Article 9) to
        keep in good order, condition and repair the roof, exterior walls
        (including exterior glass) and structure of the Building (including all
        plumbing, mechanical and electrical systems installed by Landlord, but
        specifically excluding any supplemental heating, ventilation or air
        conditioning equipment or systems installed at Tenant's request or as a
        result of Tenant's requirements in excess of building standard design
        criteria), all insofar as they affect the Premises, except that Landlord
        shall in no event be responsible to Tenant for the repair of glass in
        the Premises, or any condition in the Premises or the Building caused by
        any act or neglect of Tenant, its agents, employees, invitees or
        contractors. Landlord shall not be responsible to make any improvements
        or repairs to the Building other than as expressly in this Section 7.1
        provided, unless expressly provided otherwise in this Lease.

        (b) Landlord shall never be liable for any failure to make repairs which
        Landlord has undertaken to make under the provisions of this Section 7.1
        or elsewhere in this Lease, unless Tenant has given notice to Landlord
        of the need to make such repairs, and Landlord has failed to commence to
        make such repairs within a reasonable time after receipt of such notice,
        or fails to proceed with reasonable diligence to complete such repairs.

                                       14


<PAGE>   18



7.2     TENANT'S AGREEMENT. (a) Tenant will keep neat and clean and maintain in
        good order, condition and repair the Premises and every part thereof,
        excepting only those repairs for which Landlord is responsible under the
        terms of this Lease, reasonable wear and tear of the Premises, and
        damage by fire or other casualty or as a consequence of the exercise of
        the power of eminent domain; and shall surrender the Premises, at the
        end of the Term, in such condition. Without limitation, Tenant shall
        continually during the Term of this Lease maintain the Premises in
        accordance with all laws, codes and ordinances from time to time in
        effect and all directions, rules and regulations of the proper officers
        of governmental agencies having jurisdiction, and the standards
        recommended by the Boston Board of Fire Underwriters, and shall, at
        Tenant's expense, obtain all permits, licenses and the like required by
        applicable law. To the extent that the Premises constitute a "Place of
        Public Accommodation" within the meaning of the Americans With
        Disabilities Act of 1990, Tenant shall be responsible, subject to the
        requirements of Section 5.2, for making the Premises comply with such
        Act. Notwithstanding the foregoing or the provisions of Article XII, to
        the maximum extent this provision may be enforceable according to law,
        Tenant shall be responsible for the cost of repairs which may be made
        necessary by reason of damage to the Building caused by any act or
        neglect of Tenant, or its contractors or invitees (including any damage
        by fire or other casualty arising therefrom) and, if the premium or
        rates payable with respect to any policy or policies of insurance
        purchased by Landlord or Agent with respect to the Property increases as
        a result of payment by the insurer of any claim arising from the any act
        or neglect of Tenant, or its contractors or invitees, Tenant shall be
        pay such increase, from time to time, within fifteen (15) days after
        demand therefor by Landlord, as an additional charge.

        (b) If repairs are required to be made by Tenant pursuant to the terms
        hereof, Landlord may demand that Tenant make the same forthwith, and if
        Tenant refuses or neglects to commence such repairs and complete the
        same with reasonable dispatch, after such demand (except in the case of
        an emergency, in which event Landlord may make such repairs
        immediately), Landlord may (but shall not be required to do so) make or
        cause such repairs to be made (the provisions of Section 14.18 being
        applicable to the costs thereof), and shall not be responsible to Tenant
        for any loss or damage whatsoever that may accrue to Tenant's stock or
        business by reason thereof.

7.3     FLOOR LOAD - HEAVY MACHINERY. (a) Tenant shall not place a load upon any
        floor in the Premises exceeding the lesser of fifty (50) pounds per
        square foot, live load, or that which is allowed by law. Landlord
        reserves the right to prescribe the weight and position of all business
        machines and mechanical equipment, including safes, which shall be
        placed so as to distribute the weight. Business machines and mechanical
        equipment shall be placed and maintained by Tenant at Tenant's expense
        in settings sufficient, in Landlord's judgment, to absorb and prevent
        vibration, noise and annoyance. Tenant shall not move any safe, heavy
        machinery, heavy equipment, freight, bulky matter or fixtures into or
        out of the Building without Landlord's prior consent, which consent may
        include a requirement to provide insurance, naming Landlord as an
        insured, in such amounts as Landlord may deem reasonable.

        (b) If any such safe, machinery, equipment, freight, bulky matter or
        fixtures requires special handling, Tenant agrees to employ only persons
        holding a Master Rigger's License to do such work, and that all work in
        connection therewith shall comply with applicable laws and regulations.
        Any such moving shall be at the sole risk and hazard of Tenant, and
        Tenant will exonerate, indemnify and save Landlord harmless against and
        from any liability, loss, injury, claim or suit resulting directly or
        indirectly from such moving.


                                       15


<PAGE>   19


7.4     BUILDING SERVICES. (a) Landlord shall furnish, 24 hours per day, 7 days
        per week, heating and cooling as normal seasonal changes may require to
        provide reasonably comfortable space temperature and ventilation for
        occupants of the Premises under normal business operation at an
        occupancy of not more than one person per 150 square feet of Premises
        Rentable Area and an electrical load not exceeding 6.0 watts per square
        foot of Premises Rentable Area. In the event Tenant introduces into the
        Premises personnel or equipment which overloads the capacity of the
        Building system or in any other way interferes with the system's ability
        to perform adequately its proper functions, supplementary systems may,
        if and as needed, at Landlord's option, be provided by Landlord, at
        Tenant's expense.

        (b) Landlord shall also provide:

            (i) Passenger elevator service from the existing passenger 
            elevator system.

            (ii) Domestic water service (at temperatures supplied by the city in
            which the Property is located) for drinking, lavatory and toilet
            purposes, and connection to the municipal sewer system.

            (iii) Snow and ice removal to the walks, driveways and parking areas
            which Tenant is entitled to use under this Lease, and landscaping of
            the surrounding grounds.

            (iv) Free access to the Premises at all times, subject to security
            precautions from time to time in effect, and subject always to
            restrictions based on emergency conditions.

            (v) Nightly cleaning and janitorial services to the Building on
            Business Days, provided the same are kept in reasonable order by
            Tenant, and window-washing, all substantially in accordance with the
            cleaning standards from time to time in effect for the Building.

            (vi) Until such time as a traffic signal (or other similar traffic
            control system) is installed at the entrance to the Property, or
            until such other traffic abatement measures as the City of Waltham
            may deem appropriate are completed, the services of a police or
            other appropriate traffic control officer at the entrance to the
            Property between the hours of 4:30 and 6:30 p.m. on Business Days
            (provided that, if Tenant shall desire that such services continue
            after such signal, system or measures are in place, Landlord shall
            continue such services at the sole cost and expense of Tenant).

        (c) Landlord shall have no obligation whatsoever to provide any security
        for the Premises or the Property. If and to the extent that Tenant
        desires to provide security for the Premises or for Tenant's employees
        and invitees or their property, Tenant shall be responsible for so
        doing. Tenant agrees that, as between Landlord and Tenant, it is
        Tenant's responsibility to advise its agents, employees, contractors and
        invitees as to the foregoing and as to necessary and appropriate safety
        precautions. Without in any way limiting the operation of Article 10
        hereof, Tenant, for itself and its agents, employees, contractors and
        invitees, hereby expressly waives any claim, action, cause

                                      16


<PAGE>   20


        of action or other right which may accrue or arise against Landlord as a
        result of any damage or injury to the person or property of Tenant or
        any such agent, invitee, contractor or employee, except to the extent
        that the same arises from the negligent act or omission of Landlord or
        its agents, employees or contractors, and will indemnify and hold
        Landlord harmless from and against any loss, cost, damage or expense
        suffered by Landlord as a result of any such claim, action, cause of
        action or other right.

7.5     UTILITIES. (a) Tenant acknowledges that Basic Rent does not include the
        cost of providing any electricity to the Premises and the Property.
        Tenant shall pay for all utilities provided separately to the Premises,
        and in addition, Tenant shall pay one-half (1/2) of the cost of
        providing parking lot and other exterior lighting on the Property and
        the adjacent property on which 400-2 Totten Pond Road is located.
        Landlord shall arrange for Tenant's reasonable and customary
        requirements for utilities, including, but not limited to, gas, water,
        electricity (up to 6.0 watts per square foot of Premises Rentable Area),
        sewer charges, and the like, including all utilities necessary for
        heating and air-conditioning the Building, and Tenant shall reimburse
        Landlord for the costs and expenses incurred in connection therewith, as
        an additional charge, within fifteen (15) days after receipt of
        Landlord's invoice therefor. Except to the extent that the same arises
        from the grossly negligent or willful and wrongful act or omission of
        Landlord or its agents, employees or contractors, Landlord shall have no
        liability for interruption or unavailability of any utility or service.
        Landlord shall purchase and install, at Tenant's expense, all lamps,
        tubes, bulbs, starters and ballasts for the Premises, and shall operate
        the utility systems for only their intended uses, consistent with
        accepted building operating standards.


                                    ARTICLE 8
                                    ---------

                                REAL ESTATE TAXES
                                -----------------


8.1     PAYMENTS ON ACCOUNT OF REAL ESTATE TAXES. (a) For the purposes of this
        Article, the term "Tax Year" shall mean the twelve-month period
        commencing on the July 1 immediately preceding the Commencement Date and
        each twelve-month period thereafter commencing during the Term of this
        Lease; and the term "Taxes" shall mean an amount equal to fifty percent
        (50%) of real estate taxes assessed with respect to the Property and
        400-2 Totten Pond Road for any Tax Year commencing with the Tax Year
        beginning July 1, 1997. If the Property shall hereafter be assessed as a
        taxable parcel separate and apart from 400-2 Totten Pond Road, then 100%
        thereof shall be included in the definition of "Taxes."

        (b) In the event that for any reason, Taxes during any Tax Year shall
        exceed Base Taxes, Tenant shall pay to Landlord, as an Escalation
        Charge, an amount equal to (i) the excess of Taxes over Base Taxes for
        such Tax Year, multiplied by (ii) the Escalation Factor, such amount to
        be apportioned for any portion of a Tax Year in which the Commencement
        Date falls or the Term of this Lease ends.

        (c) Estimated payments by Tenant on account of Taxes shall be made,
        commencing July 1, 1998, on the first day of each and every calendar
        month during the Term of this Lease, in the fashion herein provided for
        the payment of Basic Rent. The monthly amount so to be paid to Landlord
        shall be sufficient to provide Landlord by the time real estate tax
        payments are due with a sum equal to

                                      17


<PAGE>   21


        Tenant's required payments, as estimated by Landlord from time to time,
        on account of Taxes for the then current Tax Year. Promptly after
        receipt by Landlord of bills for such Taxes, Landlord shall advise
        Tenant of the amount thereof and the computation of Tenant's payment on
        account thereof. If estimated payments theretofore made by Tenant for
        the Tax Year covered by such bills exceed the required payments on
        account thereof for such Year, Landlord shall credit the amount of
        overpayment against subsequent obligations of Tenant on account of Basic
        Rent for the next succeeding month (or refund such overpayment if the
        Term of this Lease has ended and Tenant has no further obligation to
        Landlord); but if the required payments on account thereof for such Year
        are greater than estimated payments theretofore made on account thereof
        for such Year, Tenant shall make payment to Landlord within 30 days
        after being so advised by Landlord.

8.2     ABATEMENT. (a) If Landlord shall receive any tax refund or reimbursement
        of Taxes or sum in lieu thereof with respect to any Tax Year, then out
        of any balance remaining thereof after deducting Landlord's expenses
        reasonably incurred in obtaining such refund, Landlord shall pay to
        Tenant, provided there does not then exist a Default of Tenant, an
        amount equal to such refund or reimbursement or sum in lieu thereof
        (together with Tenant's share of any interest actually received by
        Landlord in connection with such abatement) multiplied by the Escalation
        Factor; provided, that in no event shall Tenant be entitled to receive
        more than the payments made by Tenant on account of Taxes for such Tax
        Year pursuant to paragraph (b) of Section 8.1 or to receive any payments
        or abatement of Basic Rent if Taxes for any year are less than Base
        Taxes or Base Taxes are abated.

        (b) Landlord shall advise Tenant as to any arrangement that has been
        entered into by Landlord with relevant taxing authorities as to
        assessments for any particular Tax Year(s). So long as Landlord has not
        entered into any such arrangement for any Tax Year in question, and
        provided that Tenant requests in writing that Landlord do so (which
        request is received not less than seven (7) days prior to the last date
        on which real estate tax abatement proceedings for a particular Tax Year
        may be commenced), and Tenant agrees therein to make the payment
        referred to below), Landlord will institute and prosecute proceedings
        for an abatement of Taxes for such Tax Year. The manner and method of
        conducting such proceedings shall be solely within the reasonable
        judgment and discretion of Landlord, provided that Landlord shall not
        cancel or withdraw any such proceedings unless Landlord shall, at least
        fifteen (15) days prior thereto have notified Tenant of its intention so
        to do and Tenant shall have failed during such period to notify Landlord
        of its intention to continue such proceedings at its cost and expense.
        The obligation of Landlord to prosecute such proceedings shall not be
        applicable to any proceeding beyond the Appellate Tax Board. From time
        to time, upon ten (10) days' notice, Tenant shall pay to Landlord the
        actual and reasonable cost and expense incurred by Landlord in
        connection with such proceedings. It is understood and agreed that
        Tenant shall be responsible for the entire cost and expense of such
        proceeding, and not only 50% thereof. If Tenant shall fail to make any
        such payment within such 10-day period, Landlord shall thereafter be
        free from any further obligations under this paragraph. In the event
        that Landlord is successful in obtaining an abatement, any costs
        theretofore advanced by Tenant shall (to the extent of the amount of the
        amount refunded in account of such abatement) be repaid to Tenant prior
        to distributing the net proceeds of such abatement to Tenant and tenants
        of 400-2 Totten Pond Road entitled thereto.

8.3     ALTERNATE TAXES. (a) If some method or type of taxation shall replace
        the current method of assessment of real estate taxes in whole or part,
        or the type thereof, or if additional types of taxes are imposed upon
        the Property or Landlord, Tenant agrees that such taxes or other charges
        shall be deemed to be, and shall be, Taxes hereunder and Tenant shall
        pay an equitable share of the same as an additional charge computed in a
        fashion consistent with the method of computation herein

                                       18


<PAGE>   22


        provided, to the end that Tenant's share thereof shall be, to the
        maximum extent practicable, comparable to that which Tenant would bear
        under the foregoing provisions.

        (b) If a tax (other than a Federal or State net income tax) is assessed
        on account of the rents or other charges payable by Tenant to Landlord
        under this Lease, Tenant agrees to pay the same as an additional charge
        within ten (10) days after billing therefor, unless applicable law
        prohibits the payment of such tax by Tenant.


                                    ARTICLE 9
                                    ---------

                         OPERATING AND UTILITY EXPENSES
                         ------------------------------
     

9.1     DEFINITIONS.  For the purposes of this Article, the following terms 
        shall have the following respective meanings:

        Operating Year:  Each calendar year in which any part of the Term of 
        this Lease shall fall.

        Operating Expenses: aggregate costs or expenses reasonably incurred by
        Landlord with respect to the operation, administration, cleaning,
        repair, maintenance and management of the TPR Properties, all as set
        forth in EXHIBIT OC annexed hereto; provided that, if during any portion
        of any Operating Year for which Operating Expenses are being computed,
        less than all of the TPR Properties are occupied by tenants or if
        Landlord was not supplying all tenants with the services being supplied
        to Tenant hereunder, actual Operating Expenses incurred shall be
        reasonably extrapolated by Landlord on an item-by-item basis to the
        reasonable Operating Expenses that would have been incurred if the TPR
        Properties were fully occupied and such services were being supplied to
        all tenants, and such extrapolated Operating Expenses shall, for all
        purposes hereof, be deemed to be the Operating Expenses for such
        Operating Year.

9.2     TENANT'S PAYMENTS. (a) In the event that, for any Operating Year,
        Operating Expenses shall exceed Base Operating Expenses, Tenant shall
        pay to Landlord, as an Escalation Charge, an amount equal to (i) such
        excess Operating Expenses multiplied by (ii) the Escalation Factor, such
        amount to be apportioned for any portion of an Operating Year in which
        the Commencement Date falls or the Term of this Lease ends.

        (b) Estimated payments by Tenant on account of Operating Expenses shall
        be made, commencing January 1, 1998, on the first day of each and every
        calendar month during the Term of this Lease, in the fashion herein
        provided for the payment of Basic Rent. The monthly amount so to be paid
        to Landlord shall be sufficient to provide Landlord by the end of each
        Operating Year a sum equal to Tenant's required payments, as estimated
        by Landlord from time to time during each Operating Year, on account of
        Operating Expenses for such Operating Year. If Tenant so requests,
        Landlord shall submit to Tenant, prior to the time at which any
        estimated increase becomes effective, reasonable budget information as
        to those items of Operating Expenses for which Landlord has estimated an
        increase. After the end of each Operating Year, Landlord shall submit to
        Tenant a reasonably detailed accounting of Operating Expenses for such
        Year, and Landlord shall certify to the accuracy thereof. If estimated
        payments theretofore made for such Year by Tenant exceed Tenant's
        required payment on account thereof for such Year, according to such
        statement, Landlord

                                      19


<PAGE>   23


        shall credit the amount of overpayment against subsequent obligations of
        Tenant with respect to Operating Expenses (or refund such overpayment if
        the Term of this Lease has ended and Tenant has no further obligation to
        Landlord); but, if the required payments on account thereof for such
        Year are greater than the estimated payments (if any) theretofore made
        on account thereof for such Year, Tenant shall make payment to Landlord
        within 30 days after being so advised by Landlord. Landlord shall have
        the same rights and remedies for the nonpayment by Tenant of any
        payments due on account of Operating Expenses as Landlord has hereunder
        for the failure of Tenant to pay Basic Rent.

9.3     TENANT AUDIT RIGHTS. (a) If Tenant shall so request, within 60 days
        after receipt of any accounting required to be presented by Landlord
        hereunder, Landlord shall permit Tenant, at Tenant's expense and during
        normal business hours, to review at Landlord's office Landlord's
        invoices relating to Operating Expenses for the Operating Year in
        respect of which such accounting was prepared for the purpose of
        verifying any accounting that Landlord is required to give hereunder.
        Any such request shall be accompanied by a statement setting forth, in
        reasonable detail, the particular respects which Tenant disputes or
        questions such accounting. In making any such examination, Tenant
        agrees, and shall cause its auditors, accountants and any other
        employees, agents or contractors having access to such information to
        agree, to keep strictly confidential (i) any and all information
        contained in such books and records, and (ii) the circumstances and
        details pertaining to such examination, including without limitation the
        nature of any dispute in respect of Operating Expenses and the nature or
        details of any settlement thereof; and Tenant will confirm and cause its
        auditors, accountants, employees, agents and contractors to confirm such
        agreement in writing, if so requested by Landlord, prior to such
        examination. If Tenant shall not request any such review within the
        60-day period hereinabove referred to, then Landlord's accounting shall
        be binding and conclusive. During the pendency of any such examination,
        Tenant shall make all payments claimed by Landlord to be due, such
        payments to be without prejudice to Tenant's position.

        (b) If Tenant elects to conduct such an examination, as provided in
        paragraph (a), then any such accounting by Landlord shall be binding and
        conclusive upon Tenant unless, within one hundred fifty (150) days after
        receipt of such accounting, Tenant shall notify Landlord in writing that
        Tenant disputes the correctness of such accounting, specifying the
        particular respects in which the accounting is claimed to be incorrect.
        If such dispute has not been resolved by agreement within thirty (30)
        days after Tenant's notice of such dispute, then Tenant may, within
        thirty (30) additional days after the expiration of the first such
        30-day period, submit the matter to arbitration in accordance with the
        Commercial Arbitration Rules of the American Arbitration Association,
        except that there shall be only one arbitrator, who shall have had at
        least ten (10) years' experience as a certified property manager in
        buildings similar to the Building and in the same general location and
        market. If Tenant shall fail to submit the matter to arbitration within
        such additional 30-day period, then the accounting shall be conclusively
        deemed to be correct. Pending resolution by agreement or arbitration,
        Tenant shall make any payments claimed by Landlord to be due on account
        of Operating Expenses, such payment to be without prejudice to Tenant's
        position. Any decision by an arbitrator shall be final and binding on
        the parties. If the dispute shall be resolved in Tenant's favor,
        Landlord shall forthwith credit the amount overpaid by Tenant against
        amounts subsequently coming due on account of Operating Expenses. Each
        party shall bear one-half (1/2) of the cost of such arbitrator.



                                      20


<PAGE>   24


                                   ARTICLE 10
                                   ----------

                    INDEMNITY AND PUBLIC LIABILITY INSURANCE
                    ----------------------------------------



10.1    INDEMNITY. (a) Except to the extent that such claims arise from the
        negligent acts or omissions of Landlord or its agents or employees,
        Tenant agrees to indemnify and save harmless Landlord from and against
        all claims, loss, cost, damage or expense of whatever nature arising:
        (i) from any accident, injury or damage whatsoever to any person, or to
        the property of any person, occurring in or about the Premises after the
        Commencement Date or the date on which Tenant first occupies any part of
        the Premises (whichever occurs first); (ii) from any accident, injury or
        damage occurring outside of the Premises but on the Property where such
        accident, damage or injury results or is claimed to have resulted from
        an act or omission on the part of Tenant or Tenant's agents or employees
        or independent contractors; or (iii) in connection with the conduct or
        management of the Premises or of any business therein, or any thing or
        work whatsoever done, or any condition created (other than by Landlord)
        in or about the Premises; and, in any case, occurring after the date of
        this Lease until the end of the Term of this Lease and thereafter so
        long as Tenant is in occupancy of any part of the Premises. This
        indemnity and hold harmless agreement shall include indemnity against
        all losses, costs, damages,expenses and liabilities incurred in or in
        connection with any such claim or proceeding brought thereon, and the
        defense thereof, including, without limitation, reasonable attorneys'
        fees and costs at both the trial and appellate levels.

        (b) Landlord agrees to indemnify and save harmless Tenant from and
        against all claims, loss, cost, damage or expense of whatever nature
        arising from any accident, injury or damage, to the extent that such
        accident, damage or injury results from an act or omission on the part
        of Landlord or Landlord's agents or employees and occurring after the
        date of this Lease until the end of the Term of this Lease. This
        indemnity and hold harmless agreement shall include indemnity against
        all losses, costs, damages, expenses and liabilities incurred in or in
        connection with any such claim or proceeding brought thereon, and the
        defense thereof, including, without limitation, reasonable attorneys'
        fees and costs at both the trial and appellate levels.

10.2    PUBLIC LIABILITY INSURANCE. Tenant agrees to maintain in full force from
        the date upon which Tenant first enters the Premises for any reason,
        throughout the Term of this Lease, and thereafter so long as Tenant is
        in occupancy of any part of the Premises, a policy of commercial general
        liability and property damage insurance (including broad form
        contractual liability, independent contractor's hazard and completed
        operations coverage) under which Tenant is named as an insured and
        Landlord, Agent (and such other persons as are in privity of estate with
        Landlord as may be set out in a notice from time to time) are named as
        additional insureds, and under which the insurer agrees to indemnify and
        hold Landlord, Agent and those in privity of estate with Landlord,
        harmless from and against all cost, expense and/or liability arising out
        of or based upon any and all claims, accidents, injuries and damages set
        forth in Section 10.1. Each such policy shall be non-cancelable and
        non-amendable with respect to Landlord, Agent and Landlord's said
        designees without thirty (30) days' prior notice, shall be written on an
        "occurrence" basis, and shall be in at least the amounts of the Initial
        Public Liability Insurance specified in Section 1.3 or such greater
        amounts as Landlord shall from time to time request, and a duplicate
        original thereof shall be delivered to Landlord.


                                       21


<PAGE>   25


10.3    TENANT'S RISK. Tenant agrees to use and occupy the Premises and to use
        such other portions of the Property as Tenant is herein given the right
        to use at Tenant's own risk. Except to the extent that such claims arise
        from the negligent or wrongful acts or omissions of Landlord or its
        agents or employees, neither Landlord nor Landlord's insurers shall have
        any responsibility or liability for any loss of or damage to Tenant's
        Removable Property. Tenant shall carry "all-risk" property insurance on
        a "replacement cost" basis, insuring Tenant's Removable Property and any
        alterations, additions or improvements installed by Tenant pursuant to
        Section 5.2, to the extent that the same have not become the property of
        Landlord, and other so-called improvements and betterments. The
        provisions of this Section 10.3 shall be applicable from and after the
        execution of this Lease and until the end of the Term of this Lease, and
        during such further period as Tenant may use or be in occupancy of any
        part of the Premises or of the Building.

10.4    INJURY CAUSED BY THIRD PARTIES. Except to the extent that such claims
        arise from the negligent acts or omissions of Landlord or its agents or
        employees, Tenant agrees that Landlord shall not be responsible or
        liable to Tenant, or to those claiming by, through or under Tenant, for
        any loss or damage that may be occasioned by or through the acts or
        omissions of persons occupying adjoining premises or any part of the
        Property adjacent to or connecting with the Premises or any part of the
        Property or otherwise.


                                   ARTICLE 11
                                   ----------

                          LANDLORD'S ACCESS TO PREMISES
                          -----------------------------



11.1    LANDLORD'S RIGHTS. Landlord and Agent shall have the right, subject to
        Tenant's reasonable security restrictions set forth in EXHIBIT TS, to
        enter the Premises at all reasonable hours for the purpose of inspecting
        or making repairs to the same, and Landlord and Agent shall also have
        the right, subject to such restrictions, to make access available at all
        reasonable hours to prospective or existing mortgagees, purchasers or,
        during the last twelve months of the Term of this Lease, tenants of any
        part of the TPR Properties.


                                   ARTICLE 12
                                   ----------

                           FIRE, EMINENT DOMAIN, ETC.
                           --------------------------


12.1    ABATEMENT OF RENT. If the Premises shall be damaged by fire or casualty,
        Basic Rent and Escalation Charges payable by Tenant shall abate
        proportionately for the period in which, by reason of such damage, there
        is substantial interference with Tenant's use of the Premises, having
        regard for the extent to which Tenant may be required to discontinue
        Tenant's use of all or a portion of the Premises, but such abatement or
        reduction shall end if and when Landlord shall have substantially
        restored the Premises (excluding any alterations, additions or
        improvements made by Tenant pursuant to Section 5.2) to the condition in
        which they were prior to such damage. If the Premises shall be affected
        by any exercise of the power of eminent domain, Basic Rent and
        Escalation Charges payable by Tenant shall be justly and equitably
        abated and reduced according to the nature and extent of the loss of use
        thereof suffered by Tenant. In no event shall Landlord

                                       22


<PAGE>   26


        have any liability for damages to Tenant for inconvenience, annoyance,
        or interruption of business arising from such fire, casualty or eminent
        domain.

12.2    RIGHTS OF TERMINATION. (a) If the Premises or the Building are
        substantially damaged by fire or casualty (the term "substantially
        damaged" meaning damage of such a character that the same cannot, in
        ordinary course, reasonably be expected to be repaired within one
        hundred eighty (180) days from the time that repair work would
        commence), or if any part of the Building is taken by any exercise of
        the right of eminent domain, then Landlord shall have the right to
        terminate this Lease (even if Landlord's entire interest in the Premises
        may have been divested) by giving notice of Landlord's election so to do
        within sixty (60) days after the occurrence of such casualty or the
        effective date of such taking, whereupon this Lease shall terminate 30
        days after the date of such notice with the same force and effect as if
        such date were the date originally established as the expiration date
        hereof.

        (b) If Landlord does not elect to terminate this Lease pursuant to
        paragraph (a), then Landlord shall obtain from Landlord's architect or
        engineer, and deliver to Tenant, a written and stamped determination and
        certification as to such architect's or engineer's opinion as to the
        time that would reasonably be required to substantially complete the
        necessary repair and restoration of such damage. If such certification
        reflects that such damage cannot reasonably be expected to be
        substantially repaired within nine (9) months from date of commencement
        of such work, Tenant shall have the right to terminate this Lease by
        giving notice to Landlord thereof within fifteen (15) days after the
        receipt of such certification. This Lease shall cease and come to an end
        without further liability or obligation on the part of either party
        thirty (30) days after such giving of notice by Tenant.

12.3    RESTORATION. If this Lease shall not have been terminated pursuant to
        Section 12.2, Landlord shall thereafter use due diligence to restore the
        Premises (excluding any alterations, additions or improvements made by
        Tenant pursuant to Section 5.2, except those that have been sufficiently
        incorporated into the Premises as to become a part thereof and be
        covered by Landlord's property damage insurance) to proper condition for
        Tenant's use and occupation, provided that Landlord's obligation shall
        be limited to the amount of insurance proceeds available therefor. If,
        for any reason, such restoration shall not be substantially completed
        within nine months after the expiration of the 90-day period referred to
        in Section (which nine-month period may be extended for such periods of
        time as Landlord is prevented from proceeding with or completing such
        restoration for any cause beyond Landlord's reasonable control, but in
        no event for more than an additional three months), Tenant shall have
        the right to terminate this Lease by giving notice to Landlord thereof
        within thirty (30) days after the expiration of such period (as so
        extended) provided that such restoration is not completed within such
        period. This Lease shall cease and come to an end without further
        liability or obligation on the part of either party thirty (30) days
        after such giving of notice by Tenant unless, within such 30-day period,
        Landlord substantially completes such restoration. Such right of
        termination shall be Tenant's sole and exclusive remedy at law or in
        equity for Landlord's failure so to complete such restoration, and time
        shall be of the essence with respect thereto.

12.4    AWARD. Landlord shall have and hereby reserves and excepts, and Tenant
        hereby grants and assigns to Landlord, all rights to recover for damages
        to the Property and the leasehold interest hereby created, and to
        compensation accrued or hereafter to accrue by reason of such taking,
        damage or destruction, and by way of confirming the foregoing, Tenant
        hereby grants and assigns,

                                       23


<PAGE>   27


        and covenants with Landlord to grant and assign to Landlord, all rights
        to such damages or compensation, and covenants to deliver such further
        assignments and assurances thereof as Landlord may from time to time
        request, and Tenant hereby irrevocably appoints Landlord its
        attorney-in-fact to execute and deliver in Tenant's name all such
        assignments and assurances. Nothing contained herein shall be construed
        to prevent Tenant from prosecuting in any condemnation proceedings a
        claim for the value of any of Tenant's Removable Property installed in
        the Premises by Tenant at Tenant's expense and for relocation expenses,
        provided that such action shall not affect the amount of compensation
        otherwise recoverable by Landlord from the taking authority.

12.5    LANDLORD'S INSURANCE. Landlord agrees to maintain in full force and
        effect, during the Term of this Lease, property damage insurance with
        such deductibles and in such amounts as may from time to time be carried
        by reasonably prudent owners of similar buildings in the area in which
        the Property is located, provided that in no event shall Landlord be
        required to carry other than fire and extended coverage insurance or
        insurance in amounts greater than the actual insurable cash value of the
        Building (excluding footings and foundations). Landlord may satisfy such
        insurance requirements by including the Property in a so-called
        "blanket" insurance policy, provided that the amount of coverage
        allocated to the Property shall fulfill the foregoing requirements.


                                   ARTICLE 13
                                   ----------

                                     DEFAULT
                                     -------


13.1    TENANT'S DEFAULT.  (a) If at any time subsequent to the date of this 
        Lease any one or more of the following events (herein referred to as a
        "Default of Tenant") shall happen:

            (i) Tenant shall fail to pay the Basic Rent, Escalation Charges or
            additional charges hereunder when due and such failure shall
            continue for five (5) full Business Days after notice to Tenant from
            Landlord; or

            (ii) Tenant shall neglect or fail to perform or observe any other
            covenant herein contained on Tenant's part to be performed or
            observed and Tenant shall fail to remedy the same within thirty (30)
            days after notice to Tenant specifying such neglect or failure, or
            if such failure is of such a nature that Tenant cannot reasonably
            remedy the same within such thirty (30) day period, Tenant shall
            fail to commence promptly to remedy the same and to prosecute such
            remedy to completion with diligence and continuity; or

            (iii) Tenant's leasehold interest in the Premises shall be taken on 
            execution or by other process of law directed against Tenant; or

            (iv) Tenant shall make an assignment for the benefit of creditors or
            shall be adjudicated insolvent, or shall file any petition or answer
            seeking any reorganization, arrangement, composition, readjustment,
            liquidation, dissolution or similar relief for itself under any
            present or future Federal, State or other statute, law or regulation
            for the relief of debtors (other than the Bankruptcy Code, as
            hereinafter defined), or shall seek or consent to or

                                       24


<PAGE>   28


            acquiesce in the appointment of any trustee, receiver or liquidator
            of Tenant or of all or any substantial part of its properties, or
            shall admit in writing its inability to pay its debts generally as
            they become due; or

            (v) An Event of Bankruptcy (as hereinafter defined) shall occur 
            with respect to Tenant; or

            (vi) There shall exist any Default of Tenant under that certain
            other lease (the "400-2 Lease"), dated as of March 4, 1996, by and
            between Landlord and Tenant (whether or not Landlord shall exercise
            any or all of its rights under the 400-2 Lease as a result of such
            Default of Tenant), it being agreed and understood by Landlord and
            Tenant that a Default of Tenant hereunder shall likewise constitute
            a Default of Tenant under the 400-2 Lease; or

            (vii) A petition shall be filed against Tenant under any law (other
            than the Bankruptcy Code) seeking any reorganization, arrangement,
            composition, readjustment, liquidation, dissolution, or similar
            relief under any present or future Federal, State or other statute,
            law or regulation and shall remain undismissed or unstayed for an
            aggregate of sixty (60) days (whether or not consecutive), or if any
            trustee, conservator, receiver or liquidator of Tenant or of all or
            any substantial part of its properties shall be appointed without
            the consent or acquiescence of Tenant and such appointment shall
            remain unvacated or unstayed for an aggregate of sixty (60) days
            (whether or not consecutive);

        then in any such case Landlord may terminate this Lease by notice to
        Tenant, specifying a date not less than five (5) days after the giving
        of such notice on which this Lease shall terminate and this Lease shall
        come to an end on the date specified therein as fully and completely as
        if such date were the date herein originally fixed for the expiration of
        the Term of this Lease, and Tenant will then quit and surrender the
        Premises to Landlord, but Tenant shall remain liable as hereinafter
        provided.

        (b) For purposes of clause (a)(v) above, an "Event of Bankruptcy" means
        the filing of a voluntary petition by Tenant, or the entry of an order
        for relief against Tenant, under Chapter 7, 11, or 13 of the Bankruptcy
        Code, and the term "Bankruptcy Code" means 11 U.S.C [Section] 101, ET 
        SEQ.. If an Event of Bankruptcy occurs, then the trustee of Tenant's 
        bankruptcy estate or Tenant as debtor-in-possession may (subject to 
        final approval of the court) assume this Lease, and may subsequently 
        assign it, only if it does the following within 60 days after the date 
        of the filing of the voluntary petition, the entry of the order for 
        relief (or such additional time as a court of competent jurisdiction 
        may grant, for cause, upon a motion made within the original 60-day 
        period):

          (i)     file a motion to assume the Lease with the appropriate court;

         (ii)     satisfy all of the following conditions, which Landlord and 
                  Tenant acknowledge to be commercially reasonable:

                  (A)   cure all Defaults of Tenant under this Lease or provide
                        Landlord with Adequate Assurance (as defined below) that
                        it will (x) cure all monetary Defaults of Tenant
                        hereunder within 10 days from the date of the

                                       25


<PAGE>   29


                        assumption; and (y) cure all nonmonetary Defaults of 
                        Tenant hereunder within 30 days from the date of the
                        assumption;

                  (B)   compensate Landlord and any other person or entity, or
                        provide Landlord with Adequate Assurance that within 10
                        days after the date of the assumption, it will
                        compensate Landlord and such other person or entity, for
                        any pecuniary loss that Landlord and such other person
                        or entity incurred as a result of any Default of Tenant,
                        the trustee, or the debtor-in-possession;

                  (C)   provide Landlord with Adequate Assurance of Future
                        Performance (as defined below) of all of Tenant's
                        obligations under this Lease; and

                  (D)   deliver to Landlord a written statement that the
                        conditions herein have been satisfied.

        (c) For purposes only of the foregoing paragraph (b), and in addition to
        any other requirements under the Bankruptcy Code, any future federal
        bankruptcy law and applicable case law, "Adequate Assurance" means at
        least meeting the following conditions, which Landlord and Tenant
        acknowledge to be commercially reasonable:

          (i)     entering an order segregating sufficient cash to pay Landlord
                  and any other person or entity under paragraph (b) above, and

         (ii)     granting to Landlord a valid first lien and security interest
                  (in form acceptable to Landlord) in all property comprising
                  the Tenant's "property of the estate," as that term is defined
                  in Section 541 of the Bankruptcy Code, which lien and security
                  interest secures the trustee's or debtor-in-possession's
                  obligation to cure the monetary and nonmonetary defaults under
                  the Lease within the periods set forth in paragraph (b) above;

        (d) For purposes only of paragraph (b), and in addition to any other
        requirements under the Bankruptcy Code, any future federal bankruptcy
        law and applicable case law, "Adequate Assurance of Future Performance"
        means at least meeting the following conditions, which Landlord and
        Tenant acknowledge to be commercially reasonable:

          (i)     the trustee or debtor-in-possession depositing with Landlord,
                  as security for the timely payment of rent and other monetary
                  obligations, an amount equal to the sum of two (2) months'
                  Basic Rent plus an amount equal to two (2) months'
                  installments on account of Operating Expenses and Taxes,
                  computed in accordance with Articles 8 and 9;

         (ii)     the trustee or the debtor-in-possession agreeing to pay in
                  advance, on each day that the Basic Rent is payable, the
                  monthly installments on account of Operating Expenses and
                  Taxes, computed in accordance with Articles 8 and 9 hereof;

        (iii)     the trustee or debtor-in-possession providing adequate 
                  assurance of the source of the rent and other consideration 
                  due under this Lease;


                                       26


<PAGE>   30


         (iv)     Tenant's bankruptcy estate and the trustee or
                  debtor-in-possession providing Adequate Assurance that the
                  bankruptcy estate (and any successor after the conclusion of
                  the Tenant's bankruptcy proceedings) will continue to have
                  sufficient unencumbered assets after the payment of all
                  secured obligations and administrative expenses to assure
                  Landlord that the bankruptcy estate (and any successor after
                  the conclusion of the Tenant's bankruptcy proceedings) will
                  have sufficient funds to fulfill Tenant's obligations
                  hereunder; and

        (e) If the trustee or the debtor-in-possession assumes the Lease under
        paragraph (b) above and applicable bankruptcy law, it may assign its
        interest in this Lease only if the proposed assignee first provides
        Landlord with Adequate Assurance of Future Performance of all of
        Tenant's obligations under the Lease, and if Landlord determines, in the
        exercise of its reasonable business judgment, that the assignment of
        this Lease will not breach any other lease, or any mortgage, financing
        agreement, or other agreement relating to the Property by which Landlord
        or the Property is then bound (and Landlord shall not be required to
        obtain consents or waivers from any third party required under any
        lease, mortgage, financing agreement, or other such agreement by which
        Landlord is then bound).

        (f) For purposes only of paragraph (e) above, and in addition to any
        other requirements under the Bankruptcy Code, any future federal
        bankruptcy law and applicable case law, "Adequate Assurance of Future
        Performance" means at least the satisfaction of the following
        conditions, which Landlord and Tenant acknowledge to be commercially
        reasonable:

            (i)   the proposed assignee submitting a current financial
                  statement, audited by a certified public accountant, that
                  allows a net worth and working capital in amounts determined
                  in the reasonable business judgment of Landlord to be
                  sufficient to assure the future performance by the assignee of
                  Tenant's obligation under this Lease; and

            (ii)  if requested by Landlord in the exercise of its reasonable
                  business judgment, the proposed assignee obtaining a guarantee
                  (in form and substance satisfactory to Landlord) from one or
                  more persons who satisfy Landlord's standards of
                  creditworthiness;

        (g) If this Lease shall have been terminated as provided in this
        Article, or if any execution or attachment shall be issued against
        Tenant or any of Tenant's property whereupon the Premises shall be taken
        or occupied by someone other than Tenant, then Landlord may re-enter the
        Premises, either by summary proceedings, ejectment or otherwise, and
        remove and dispossess Tenant and all other persons and any and all
        property from the same, as if this Lease had not been made.

        (h) In the event of any termination, Tenant shall pay the Basic Rent,
        Escalation Charges and other sums payable hereunder up to the time of
        such termination, and thereafter Tenant, until the end of what would
        have been the Term of this Lease in the absence of such termination, and
        whether or not the Premises shall have been relet, shall be liable to
        Landlord for, and shall pay to Landlord, as liquidated current damages:
        (x) the Basic Rent, Escalation Charges and other sums that would be
        payable hereunder if such termination had not occurred, less the net
        proceeds, if any, of any reletting of the Premises, after deducting all
        expenses in connection with such reletting, including, without
        limitation, all repossession costs, brokerage commissions, legal
        expenses, attorneys' fees, advertising, expenses of employees,
        alteration costs and expenses of preparation for

                                       27


<PAGE>   31


        such reletting; and (y) if, in accordance with Section 3.1(a), Tenant
        commenced payment of the full amount of Basic Rent on any day other than
        the Commencement Date, the amount of Basic Rent that would have been
        payable during the period beginning on the Commencement Date and ending
        on the day Tenant commenced payment of the full amount of Basic Rent
        under such Section 3.1(a). Tenant shall pay the portion of such current
        damages referred to in clause (x) above to Landlord monthly on the days
        which the Basic Rent would have been payable hereunder if this Lease had
        not been terminated, and Tenant shall pay the portion of such current
        damages referred to in clause (y) above to Landlord upon such
        termination.

        (i) At any time after such termination, whether or not Landlord shall
        have collected any such current damages, as liquidated final damages and
        in lieu of all such current damages beyond the date of such demand, at
        Landlord's election Tenant shall pay to Landlord an amount equal to the
        excess, if any, of the Basic Rent, Escalation Charges and other sums as
        hereinbefore provided which would be payable hereunder from the date of
        such demand assuming that, for the purposes of this paragraph, annual
        payments by Tenant on account of Taxes and Operating Expenses would be
        the same as the payments required for the immediately preceding
        Operating or Tax Year for what would be the then unexpired Term of this
        Lease if the same remained in effect, over the then fair net rental
        value of the Premises for the same period.

        (j) In case of any Default by Tenant, re-entry, expiration and
        dispossession by summary proceedings or otherwise, Landlord may (i)
        re-let the Premises or any part or parts thereof, either in the name of
        Landlord or otherwise, for a term or terms which may at Landlord's
        option be equal to or less than or exceed the period which would
        otherwise have constituted the balance of the Term of this Lease and may
        grant concessions or free rent to the extent that Landlord considers
        advisable and necessary to re-let the same and (ii) may make such
        reasonable alterations, repairs and decorations in the Premises as
        Landlord in its sole judgment considers advisable and necessary for the
        purpose of reletting the Premises; and the making of such alterations,
        repairs and decorations shall not operate or be construed to release
        Tenant from liability hereunder as aforesaid. Landlord shall in no event
        be liable in any way whatsoever for failure to re-let the Premises, or,
        in the event that the Premises are re-let, for failure to collect the
        rent under such re-letting. Tenant hereby expressly waives any and all
        rights of redemption granted by or under any present or future laws in
        the event of Tenant being evicted or dispossessed, or in the event of
        Landlord obtaining possession of the Premises, by reason of the
        violation by Tenant of any of the covenants and conditions of this
        Lease.

        (k) The specified remedies to which Landlord may resort hereunder are
        not intended to be exclusive of any remedies or means of redress to
        which Landlord may at any time be entitled lawfully, and Landlord may
        invoke any remedy (including the remedy of specific performance) allowed
        at law or in equity as if specific remedies were not herein provided
        for.

        (l) All costs and expenses incurred by or on behalf of Landlord
        (including, without limitation, attorneys' fees and expenses at both the
        trial and appellate levels) in enforcing its rights hereunder or
        occasioned by any Default of Tenant shall be paid by Tenant.

13.2    LANDLORD'S DEFAULT. Landlord shall in no event be in default in the
        performance of any of Landlord's obligations hereunder unless and until
        Landlord shall have failed to perform such obligations within thirty
        (30) days, or if such failure is of such a nature that Landlord cannot
        reasonably remedy the same within such thirty (30) day period, Landlord
        shall fail to commence

                                       28


<PAGE>   32


        promptly (and in any event within such thirty (30) day period) to remedy
        the same and to prosecute such remedy to completion with diligence and
        continuity.


                                  ARTICLE 14
                                  ----------

                           MISCELLANEOUS PROVISIONS
                           ------------------------
  

14.1    EXTRA HAZARDOUS USE. Tenant covenants and agrees that Tenant will not do
        or permit anything to be done in or upon the Premises, or bring in
        anything or keep anything therein, which shall increase the rate of
        property or liability insurance on the Premises or the Property above
        the standard rate applicable to Premises being occupied for Permitted
        Uses; and Tenant further agrees that, in the event that Tenant shall do
        any of the foregoing, Tenant will promptly pay to Landlord, on demand,
        any such increase resulting therefrom, which shall be due and payable as
        an additional charge hereunder.

14.2    WAIVER. (a) Failure on the part of Landlord or Tenant to complain of any
        action or non-action on the part of the other, no matter how long the
        same may continue, shall never be a waiver by Tenant or Landlord,
        respectively, of any of the other's rights hereunder. Further, no waiver
        at any time of any of the provisions hereof by Landlord or Tenant shall
        be construed as a waiver of any of the other provisions hereof, and a
        waiver at any time of any of the provisions hereof shall not be
        construed as a waiver at any subsequent time of the same provisions. The
        consent or approval of Landlord or Tenant to or of any action by the
        other requiring such consent or approval shall not be construed to waive
        or render unnecessary Landlord's or Tenant's consent or approval to or
        of any subsequent similar act by the other.

        (b) No payment by Tenant, or acceptance by Landlord, of a lesser amount
        than shall be due from Tenant to Landlord shall be treated otherwise
        than as a payment on account of the earliest installment of any payment
        due from Tenant under the provisions hereof. The acceptance by Landlord
        of a check for a lesser amount with an endorsement or statement thereon,
        or upon any letter accompanying such check, that such lesser amount is
        payment in full, shall be given no effect, and Landlord may accept such
        check without prejudice to any other rights or remedies which Landlord
        may have against Tenant.

14.3    COVENANT OF QUIET ENJOYMENT. Tenant, subject to the terms and provisions
        of this Lease, on payment of the Basic Rent and Escalation Charges and
        observing, keeping and performing all of the other terms and provisions
        of this Lease on Tenant's part to be observed, kept and performed, shall
        lawfully, peaceably and quietly have, hold, occupy and enjoy the
        Premises during the term hereof, without hindrance or ejection by any
        persons lawfully claiming under Landlord to have title to the Premises
        superior to Tenant; the foregoing covenant of quiet enjoyment is in lieu
        of any other covenant, express or implied.

14.4    LIMITATION OF LIABILITY. (a) Tenant specifically agrees to look solely
        to Landlord's then equity interest in the TPR Properties at the time
        owned, for recovery of any judgment from Landlord; it being specifically
        agreed that Landlord (original or successor) shall never be personally
        liable for any such judgment, or for the payment of any monetary
        obligation to Tenant. The provision contained in the foregoing sentence
        is not intended to, and shall not, limit any right that

                                      29


<PAGE>   33


        Tenant might otherwise have to obtain injunctive relief against Landlord
        or Landlord's successors in interest, or to take any action not
        involving the personal liability of Landlord (original or successor) to
        respond in monetary damages from Landlord's assets other than Landlord's
        equity interest in the TPR Properties.

        (b) With respect to any services or utilities to be furnished by
        Landlord to Tenant, Landlord shall in no event be liable for failure to
        furnish the same when prevented from doing so by strike, lockout,
        breakdown, accident, order or regulation of or by any governmental
        authority, or failure of supply, or failure whenever and for so long as
        may be necessary by reason of the making of repairs or changes which
        Landlord is required or is permitted by this Lease or by law to make or
        in good faith deems necessary, or inability by the exercise of
        reasonable diligence to obtain supplies, parts or employees necessary to
        furnish such services, or because of war or other emergency, or for any
        other cause beyond Landlord's reasonable control, or for any cause due
        to any act or neglect of Tenant or Tenant's servants, agents, employees,
        licensees or any person claiming by, through or under Tenant, nor shall
        any such failure give rise to any claim in Tenant's favor that Tenant
        has been evicted, either constructively or actually, partially or
        wholly. Notwithstanding the foregoing to the contrary, if, due to any
        event or circumstance described above or any Force Majeure, Tenant is
        prevented from receiving essential services or utilities that Landlord
        is obligated to perform or deliver under this Lease, and such
        interruption of essential services or utilities renders the Premises
        untenantable, and if such interruption shall continue for a period of
        five (5) consecutive days after notice thereof from Tenant to Landlord
        that the Premises are untenantable as a result thereof, Basic Rent and
        Escalation Charges shall abate commencing on the sixth day after such
        notice (and, if less than all of the Premises are affected by such
        interruption, such abatement shall be pro-rated according to the area so
        affected) until such time as such services or utilities are restored.
        The foregoing shall not apply to repairs or changes necessitated by fire
        or other casualty, or by the exercise of the right of eminent domain,
        which shall be governed by Article 12. Tenant's rights herein granted
        shall be Tenant's sole remedies for such interruption.

        (c) In no event shall either party ever be liable to the other for any
        loss of business or any other indirect or consequential damages suffered
        by the other from whatever cause.

        (d) Except with respect to requests by Tenant for Landlord's consent to
        a sublease permitted under Article 6, where provision is made in this
        Lease for Landlord's consent and Tenant shall request such consent and
        Landlord shall fail or refuse to give such consent, Tenant shall not be
        entitled to any damages for any withholding by Landlord of its consent,
        it being intended that Tenant's sole remedy shall be an action for
        specific performance or injunction, and that such remedy shall be
        available only in those cases where Landlord has expressly agreed in
        writing not to unreasonably withhold its consent. Furthermore, whenever
        Tenant requests Landlord's consent or approval (whether or not provided
        for herein), Tenant shall pay to Landlord, on demand, as an additional
        charge, any expenses reasonably incurred by Landlord (including without
        limitation legal fees and costs, if any) in connection therewith.

        (e) With respect to any repairs or restoration which are required or
        permitted to be made by Landlord, the same may be made during normal
        business hours and Landlord shall have no liability for damages to
        Tenant for inconvenience, annoyance or interruption of business arising
        therefrom. Landlord agrees, however, in the course of such work, to use
        all reasonable efforts not to unreasonably interfere with Tenant's
        operation in the Premises.


                                       30


<PAGE>   34


14.5    NOTICE TO MORTGAGEE OR GROUND LESSOR. After receiving notice from any
        person, firm or other entity that it holds a mortgage or a ground lease
        which includes the Premises, no notice from Tenant to Landlord alleging
        any default by Landlord shall be effective unless and until a copy of
        the same is given to such holder or ground lessor (provided Tenant shall
        have been furnished with the name and address of such holder or ground
        lessor), and the curing of any of Landlord's defaults by such holder or
        ground lessor shall be treated as performance by Landlord.

14.6    ASSIGNMENT OF RENTS AND TRANSFER OF TITLE. (a) With reference to any
        assignment by Landlord of Landlord's interest in this Lease, or the
        rents payable hereunder, conditional in nature or otherwise, which
        assignment is made to the holder of a mortgage on property which
        includes the Premises, Tenant agrees that the execution thereof by
        Landlord, and the acceptance thereof by the holder of such mortgage
        shall never be treated as an assumption by such holder of any of the
        obligations of Landlord hereunder unless such holder shall, by notice
        sent to Tenant, specifically otherwise elect and that, except as
        aforesaid, such holder shall be treated as having assumed Landlord's
        obligations hereunder only upon foreclosure of such holder's mortgage
        and/or the taking of possession of the Premises for the purpose of
        foreclosing.

        (b) In no event shall the acquisition of Landlord's interest in the
        Property by a purchaser which, simultaneously therewith, leases
        Landlord's entire interest in the Property back to the seller thereof be
        treated as an assumption by operation of law or otherwise, of Landlord's
        obligations hereunder, but Tenant shall look solely to such
        seller-lessee, and its successors from time to time in title, for
        performance of Landlord's obligations hereunder. In any such event, this
        Lease shall be subject and subordinate to the lease to such purchaser.
        For all purposes, such seller-lessee, and its successors in title, shall
        be the Landlord hereunder unless and until Landlord's position shall
        have been assumed by such purchaser-lessor. Notwithstanding the
        foregoing, Landlord agrees to obtain the written agreement of the
        purchaser-lessor that, subject to such reasonable qualifications as such
        purchaser-lessor may reasonably impose, in the event that the
        purchaser-lessor shall succeed to the interests of Landlord hereunder
        pursuant to such lease, then so long as no Default of Tenant exists
        hereunder, Tenant's right to possession of the Premises shall not be
        disturbed and Tenant's other rights hereunder shall not be adversely
        affected by termination of such lease.

        (c) Except as provided in paragraph (b) of this Section, in the event of
        any transfer of title to the Property by Landlord, Landlord shall
        thereafter be entirely freed and relieved from the performance and
        observance of all covenants and obligations hereunder, except to the
        extent that Tenant shall have given Landlord written notice, prior to
        the date of such transfer, of any claim.

14.7    RULES AND REGULATIONS. Tenant shall abide by rules and regulations from
        time to time established by Landlord, it being agreed that such rules
        and regulations will be established and applied by Landlord in a
        non-discriminatory fashion, such that all rules and regulations shall be
        generally applicable to other tenants, if any, of similar nature to the
        Tenant named herein, of the Building. Landlord agrees to use reasonable
        efforts to insure that any such rules and regulations are uniformly
        enforced, but Landlord shall not be liable to Tenant for violation of
        the same by any other tenant or occupant of the Building, or persons
        having business with them. In the event that there shall be a conflict
        between such rules and regulations and the provisions of this Lease, the
        provisions of this Lease shall control. Rules and Regulations currently
        in effect are set forth in EXHIBIT RR.


                                       31


<PAGE>   35


14.8    ADDITIONAL CHARGES. If Tenant shall fail to pay when due any sums under
        this Lease designated as an Escalation Charge or additional charge,
        Landlord shall have the same rights and remedies as Landlord has
        hereunder for failure to pay Basic Rent.

14.9    INVALIDITY OF PARTICULAR PROVISIONS. If any term or provision of this
        Lease, or the application thereof to any person or circumstance shall,
        to any extent, be invalid or unenforceable, the remainder of this Lease,
        or the application of such term or provision to persons or circumstances
        other than those as to which it is held invalid or unenforceable, shall
        not be affected thereby, and each term and provision of this Lease shall
        be valid and be enforced to the fullest extent permitted by law.

14.10   PROVISIONS BINDING, ETC. Except as herein otherwise provided, the terms
        hereof shall be binding upon and shall inure to the benefit of the
        successors and assigns, respectively, of Landlord and Tenant (except in
        the case of Tenant, ONLY such assigns as may be permitted hereunder)
        and, if Tenant shall be an individual, upon and to his heirs, executors,
        administrators, successors and permitted assigns. Each term and each
        provision of this Lease to be performed by Tenant shall be construed to
        be both a covenant and a condition. The reference contained to
        successors and assigns of Tenant is not intended to constitute a consent
        to assignment by Tenant, but has reference only to those instances in
        which Landlord may later give consent to a particular assignment as
        required by those provisions of Article 6 hereof.

14.11   RECORDING. Tenant agrees not to record this Lease, but, if the Term of
        this Lease (including any extended term) is seven (7) years or longer,
        each party hereto agrees, on the request of the other, to execute a
        so-called notice of lease in recordable form and complying with
        applicable law and reasonably satisfactory to Landlord's attorneys. In
        no event shall such document set forth the rent or other charges payable
        by Tenant under this Lease; and any such document shall expressly state
        that it is executed pursuant to the provisions contained in this Lease,
        and is not intended to vary the terms and conditions of this Lease.

14.12   NOTICES. Whenever, by the terms of this Lease, notices shall or may be
        given either to Landlord or to Tenant, such notice shall be in writing
        and shall be sent by registered or certified mail, postage prepaid,
        return receipt requested:

        If intended for Landlord, addressed to Landlord at Landlord's Original
        Address and marked: "Attention: Asset Manager, 400/460 Totten Pond
        Road," with a copy to Stephen T. Langer, Esq., Mintz, Levin, Cohn,
        Ferris, Glovsky and Popeo, P.C., One Financial Center, Boston, MA 02111
        (or to such other address or addresses as may from time to time
        hereafter be designated by Landlord by like notice).

        If intended for Tenant, addressed to Tenant at Tenant's Original Address
        (or to such other address or addresses as may from time to time
        hereafter be designated by Tenant by like notice), with a copy to
        Douglas M. Henry, Esq., Bingham, Dana & Gould, 150 Federal Street,
        Boston, MA 02110.

        All such notices shall be effective when deposited in the United States
        Mail within the Continental United States, provided that the same are
        received in ordinary course at the address to which the same were sent.


                                       32


<PAGE>   36


14.13   WHEN LEASE BECOMES BINDING. The submission of this document for 
        examination and negotiation does not constitute an offer to lease, or a
        reservation of, or option for, the Premises, and this document shall
        become effective and binding only upon the execution and delivery hereof
        by both Landlord and Tenant. All negotiations, considerations,
        representations and understandings between Landlord and Tenant are
        incorporated herein and this Lease expressly supersedes any proposals or
        other written documents relating hereto. This Lease may be modified or
        altered only by written agreement between Landlord and Tenant, and no
        act or omission of any employee or agent of Landlord shall alter, change
        or modify any of the provisions hereof.

14.14   PARAGRAPH HEADINGS AND INTERPRETATION OF SECTIONS.  The paragraph 
        headings throughout this instrument are for convenience and reference
        only, and the words contained therein shall in no way be held to
        explain, modify, amplify or aid in the interpretation, construction or
        meaning of the provisions of this Lease. The provisions of this Lease
        shall be construed as a whole, according to their common meaning (except
        where a precise legal interpretation is clearly evidenced), and not for
        or against either party. Use in this Lease of the words "including,"
        "such as" or words of similar import, when followed by any general term,
        statement or matter, shall not be construed to limit such term,
        statement or matter to the specified item(s), whether or not language of
        non-limitation, such as "without limitation" or "including, but not
        limited to," or words of similar import, are used with reference
        thereto, but rather shall be deemed to refer to all other terms or
        matters that could fall within a reasonably broad scope of such term,
        statement or matter.

14.15   RIGHTS OF MORTGAGEE OR GROUND LESSOR. This Lease shall be subordinate to
        any mortgage or ground lease from time to time encumbering the Premises,
        whether executed and delivered prior to or subsequent to the date of
        this Lease, if the holder of such mortgage or ground lease shall so
        elect. If this Lease is subordinate to any mortgage or ground lease and
        the holder thereof (or successor) shall succeed to the interest of
        Landlord, at the election of such holder (or successor) Tenant shall
        attorn to such holder and this Lease shall continue in full force and
        effect between such holder (or successor) and Tenant. Tenant agrees to
        execute such instruments of subordination or attornment in confirmation
        of the foregoing agreement as such holder may request. Notwithstanding
        the foregoing, if the holder of such mortgage elects to make this Lease
        subordinate as aforesaid, then upon the written request of Tenant,
        Landlord shall obtain the holder's written agreement (substantially in
        the form annexed hereto as EXHIBIT SNDA) that, subject to such
        reasonable qualifications as such holder may reasonably impose, in the
        event that the holder shall succeed to the interests of Landlord
        hereunder pursuant to such mortgage, ground lease or other encumbrance,
        so long as no Default of Tenant exists hereunder, Tenant's right to
        possession of the Premises shall not be disturbed and Tenant's other
        rights hereunder shall not be adversely affected by any foreclosure of
        such mortgage or encumbrance or by termination of such ground lease.

14.16   STATUS REPORT. Recognizing that both parties may find it necessary to 
        establish to third parties, such as accountants, banks, mortgagees,
        ground lessors, or the like, the then current status of performance
        hereunder, either party, on the request of the other made from time to
        time, will promptly furnish to Landlord, or the holder of any mortgage
        or ground lease encumbering the Premises, or to Tenant, as the case may
        be, a statement of the status of any matter pertaining to this Lease,
        including, without limitation, acknowledgments that (or the extent to
        which) each party is in compliance with its obligations under the terms
        of this Lease.

14.17   SECURITY DEPOSIT. (a) Subject to Section 14.17(b), the security deposit 
        will be paid upon execution and delivery of this Lease, and Landlord
        shall hold the same throughout the Term of this

                                       33


<PAGE>   37


        Lease as security for the performance by Tenant of all obligations on
        the part of Tenant hereunder. Landlord shall have the right from time to
        time without prejudice to any other remedy Landlord may have on account
        thereof, to apply such deposit, or any part thereof, to Landlord's
        damages arising from, or to cure, any Default of Tenant hereunder or
        under any other such lease or occupancy agreement. If Landlord shall so
        apply any or all of such deposit, Tenant shall immediately deposit with
        Landlord the amount so applied to be held as security hereunder. If at
        each such time there then exists no Default of Tenant (or event or
        circumstance which, with the passage of time or the giving of notice, or
        both, would constitute a Default of Tenant), Landlord shall return the
        deposit, or so much thereof as shall have theretofore not been applied
        in accordance with the terms of this Section 14.7, to Tenant as
        follows: (i) on each of the third, fourth, fifth and sixth
        anniversaries of the Commencement Date, an amount equal to one-quarter
        (1/4) of the excess of the initial security deposit over one (1)
        month's Basic Rent; and (ii) the remainder on the expiration or earlier
        termination of the Term of this Lease and surrender of possession of
        the Premises by Tenant to Landlord at such time. While Landlord holds
        such deposit, Landlord shall hold the same in a separate account in a
        Massachusetts bank, or in a non-Massachusetts bank acceptable to
        Landlord and Tenant, and shall pay to Tenant's account the amount of
        any interest actually paid by such bank with respect thereto (after
        deducting any fees or other charges imposed on Landlord in respect of
        such account). Tenant hereby certifies that it is aware that the
        Federal Deposit Insurance Corporation ("FDIC") coverages apply only to
        a cumulative maximum amount of $100,000 for each individual deposit for
        all of depositor's accounts at the same or related institution. Tenant
        further understands that certain banking instruments such as, but not
        limited to, repurchase agreements and letters of credit, are not
        covered at all by FDIC insurance. Further, Tenant agrees that Landlord
        assumes no responsibility for, nor will Tenant hold Landlord liable
        for, any loss occurring which arises from the fact that the amount of
        the security deposit exceeds $100,000 or from the fact that the excess
        amount will not be insured by FDIC, or that FDIC insurance is not
        available on certain types of bank instruments. If Landlord conveys
        Landlord's interest under this Lease, and the transferee agrees to
        assume Landlord's obligations under this Lease, the deposit, or any
        part thereof not previously applied, shall be turned over by Landlord
        to Landlord's grantee, and, if so turned over, Tenant agrees to look
        solely to such grantee for proper application of the deposit in
        accordance with the terms of this Section 14.7, and the return thereof
        in accordance herewith. The holder of a mortgage shall not be
        responsible to Tenant for the return or application of any such
        deposit, whether or not it succeeds to the position of Landlord
        hereunder, unless such deposit shall have been actually received in
        hand by such holder.

        (b) Landlord may, in its sole discretion, require that instead of a cash
        security deposit, Tenant shall, upon execution and delivery of this
        Lease, deposit with Landlord a clean, irrevocable, unconditional letter
        of credit, with a right of assignment (without charge or cost to
        Landlord) to any successor to Landlord's interests hereunder, in favor
        of Landlord in the amount of the security deposit. In the event that
        Landlord so requires, Landlord agrees to pay the letter of credit fee
        charged by the issuing bank in respect thereof. Such letter of credit,
        and any replacement thereof, shall be drawn on a Massachusetts bank
        approved by Landlord from time to time. The form of the Letter of Credit
        annexed hereto as EXHIBIT LOC is acceptable to Landlord. In the event of
        a material adverse change in the financial position of any bank which
        has issued a letter of credit hereunder, Landlord reserves the right, on
        any scheduled expiration or renewal date of any such letter (or, in the
        event that Landlord reasonably determines that the condition of the
        issuing bank is in imminent danger of insolvency, upon 10 days' notice),
        to request that Tenant change the issuing bank to another bank
        reasonably approved by Landlord. Regardless of whether Landlord shall
        have previously requested that Tenant change issuing banks, if the bank
        on which the original letter of

                                       34


<PAGE>   38


        credit or any replacement letter is drawn is declared insolvent or
        placed into conservatorship or receivership, Tenant shall, within 20
        days thereafter, replace the then-outstanding letter of credit with a
        like letter of credit from another bank acceptable to Landlord, and
        Landlord shall reimburse Tenant for any issuance fees as hereinabove
        provided.

        (c) The letter of credit shall contain a clause whereby the issuing bank
        agrees to automatically extend the term of the letter of credit from
        year to year throughout the Initial Term (and any Extended Term) unless,
        not less than sixty (60) days prior to the date on which the letter
        would expire absent such extension, the issuing bank gives notice to
        Landlord, by certified or registered mail, of non-extension. In the
        event of notice from the issuing bank of non-extension, Tenant shall,
        not later than twenty (20) Business Days prior to the date on which the
        outstanding letter shall expire without extension, obtain a replacement
        letter of credit from a Massachusetts bank acceptable to Landlord, under
        all of the terms and conditions set forth above. Upon (i) the occurrence
        of a Default of Tenant hereunder, or (ii) the failure of Tenant to
        replace any such letter at least twenty (20) Business Days prior to its
        expiration, and written certification thereof by Landlord to the issuing
        bank, Landlord may at its election draw the full amount or any part
        thereof, and hold, use and apply the proceeds thereof as if such
        proceeds were originally deposited with Landlord in cash under this
        Section. In the event that Landlord draws any such letter of credit,
        Landlord may elect to use such proceeds (or any excess proceeds after
        application) to obtain from another Massachusetts bank a replacement
        letter of credit, and the cost of such replacement shall be deducted
        from the available balance and reimbursed by Tenant. Tenant hereby
        agrees, if so requested by Landlord, to enter into a letter of credit
        agreement with the bank so designated by Landlord, failing which
        Landlord may do so in Tenant's name and behalf. The order in which
        Landlord applies the proceeds of the cash security deposit and the
        proceeds of the letter of credit shall be determined by Landlord from
        time to time in its sole and unfettered discretion.

        (d) From and after the time at which Landlord shall have drawn all or
        any portion of the proceeds of such a letter of credit, if Landlord
        shall not elect to obtain its own replacement letter of credit, Landlord
        shall have the right from time to time without prejudice to any other
        remedy Landlord may have on account thereof, to apply such proceeds, or
        any part thereof, to Landlord's damages arising from any then existing
        or subsequently occurring Default of Tenant hereunder. While Landlord
        holds any unapplied proceeds, Landlord shall maintain a separate account
        and pay interest thereon as provided in paragraph (a). There then
        existing no Default of Tenant hereunder or under any other leases or
        occupancy agreements that may hereafter be entered into between Landlord
        and Tenant relative to the TPR Properties, Landlord shall return to
        Tenant the proceeds thereof (or, if not drawn upon, any letter of
        credit), or so much thereof as shall not have theretofore been applied
        in accordance with the terms of this Section 14.17, provided that as to
        the partial reductions in the amount of the security deposit referred to
        in paragraph (a), such reductions shall be effected by amendments to the
        letter of credit reflecting the reduced requirements. If Landlord
        conveys Landlord's interest under this Lease, and the transferee agrees
        to assume Landlord's obligations under this Lease, the proceeds (or, if
        not drawn upon, any letter of credit), or any part thereof not
        previously applied, shall be turned over by Landlord to Landlord's
        grantee, and, when actually turned over, Tenant agrees to look solely to
        such grantee for proper application of the proceeds in accordance with
        the terms of this Section 14.17, and the return thereof in accordance
        herewith. The holder of a mortgage shall not be responsible to Tenant
        for the return of any letter of credit or application of any such
        proceeds, whether or not it succeeds to the position of Landlord
        hereunder, unless such proceeds or letter of credit shall have actually
        been received by such holder.


                                       35


<PAGE>   39


14.18   REMEDYING DEFAULTS. Landlord shall have the right, but shall not be
        required, to pay such sums or do any act which requires the expenditure
        of monies which may be necessary or appropriate by reason of the failure
        or neglect of Tenant to perform any of the provisions of this Lease, and
        in the event of the exercise of such right by Landlord, Tenant agrees to
        pay to Landlord forthwith upon demand all such sums, together with
        interest thereon at a rate equal to 3% over the base rate in effect from
        time to time at The First National Bank of Boston (but in no event more
        than 18% per annum), as an additional charge. Any payment of Basic Rent,
        Escalation Charges or other sums payable hereunder not paid when due
        shall, at the option of Landlord, bear interest at a rate equal to 3%
        over the base rate in effect from time to time at The First National
        Bank of Boston (but in no event more than 18% per annum) from the due
        date thereof and shall be payable forthwith on demand by Landlord, as an
        additional charge.

14.19   HOLDING OVER. Any holding over by Tenant after the expiration of the
        term of this Lease shall be treated as a daily tenancy at sufferance at
        a rate equal to one and one-half (1 1/2) times the Basic Rent then in
        effect plus Escalation Charges and other charges herein provided
        (prorated on a daily basis). Tenant shall also pay to Landlord all
        direct damages sustained by reason of any such holding over. Otherwise,
        such holding over shall be on the terms and conditions set forth in this
        Lease as far as applicable.

14.20   WAIVER OF SUBROGATION. Insofar as, and to the extent that, the following
        provision shall not make it impossible to secure insurance coverage
        obtainable from responsible insurance companies doing business in the
        locality in which the Property is located (even though extra premium may
        result therefrom) Landlord and Tenant: (i) mutually agree that, with
        respect to any damage to property, the loss from which is covered by
        insurance then being carried by them, respectively, the one carrying
        such insurance and suffering such loss releases the other of and from,
        and forever waives, any and all claims with respect to such loss, but
        only to the extent of the limits of insurance carried with respect
        thereto, less the amount of any deductible; and (ii) mutually agree that
        any property damage insurance carried by either shall provide for the
        waiver by the insurance carrier of any right of subrogation against the
        other.

14.21   SURRENDER OF PREMISES. Upon the expiration or earlier termination of the
        Term of this Lease, Tenant shall peaceably quit and surrender to
        Landlord the Premises in neat and clean condition and in good order,
        condition and repair, together with all alterations, additions and
        improvements which may have been made or installed in, on or to the
        Premises prior to or during the Term of this Lease, excepting only
        ordinary wear and use and damage by fire or other casualty for which,
        under other provisions of this Lease, Tenant has no responsibility of
        repair or restoration. If Tenant (or Landlord, acting at the request of
        Tenant) shall have installed an "internal" staircase in the Building,
        then Tenant shall be required to remove the same and repair and restore
        any floor openings and other affected areas to their prior condition.
        Also, Tenant shall remove all of Tenant's Removable Property and, to the
        extent specified by Landlord (as of the date Landlord approved any such
        alteration or addition, if approval thereof was required under Section
        5.2), all alterations and additions made by Tenant and all partitions
        wholly within the Premises unless installed initially by Landlord in
        preparing the Premises for Tenant's occupancy; and shall repair any
        damages to the Premises or the Building caused by such removal. Any
        Tenant's Removable Property which shall remain in the Building or on the
        Premises after the expiration or termination of the Term of this Lease
        shall be deemed conclusively to have been abandoned, and either may be
        retained by Landlord as its property or may be disposed of in such
        manner as Landlord may see fit, at Tenant's sole cost and expense.

                                       36


<PAGE>   40



14.22   BROKERAGE. Tenant warrants and represents that Tenant has dealt with no
        broker in connection with the consummation of this Lease other than
        Broker, and, in the event of any brokerage claims against Landlord
        predicated upon prior dealings with Tenant, Tenant agrees to defend the
        same and indemnify Landlord against any such claim (except any claim by
        Broker, who shall be paid by Landlord).

14.23   GOVERNING LAW. This Lease shall be governed exclusively by the 
        provisions hereof and by the laws of the Commonwealth of Massachusetts
        as the same may from time to time exist.


                                  ARTICLE 15
                                  ----------

                               OPTION TO EXTEND
                               ----------------


15.1    TENANT'S RIGHT.  Provided that, at the time of such exercise, (i) there 
        exists no Default of Tenant; (ii) this Lease is still in full force and
        effect; and (iii) Tenant actually occupies at least sixty percent (60%)
        of Premises Rentable Area, Tenant shall have the right to extend the
        Term of this Lease as to the Premises originally leased hereunder for
        one extended term (the "Extended Term") of five (5) years. The Extended
        Term shall commence on the day immediately following the expiration date
        of the Initial Term, and shall end on the day immediately preceding the
        fifth anniversary of the first day of the Extended Term. Tenant shall
        exercise such option by giving Landlord notice of its desire to do so,
        not later than twelve (12) months prior to the expiration of the Initial
        Term, it being agreed that time shall be of the essence with respect to
        the giving of such notice. The giving of such notice shall automatically
        extend the Term of this Lease for the Extended Term, and no instrument
        of renewal need be executed. In the event that Tenant fails to give such
        notice to Landlord, the Term of this Lease shall automatically terminate
        at the end of the Initial Term, and Tenant shall have no further right
        or option to extend the Term of this Lease. The Extended Term shall be
        on all the terms and conditions of this Lease, except that: (i) Landlord
        shall have no obligation to pay any construction or improvements
        allowance, or to perform any alterations or improvements to the
        Premises, with respect to the Extended Term; and (ii) the Basic Rent for
        the Extended Term shall be determined in accordance with section 15.2.

15.2    EXTENDED TERM RENT. (a) The Basic Rent for the Extended Term shall be
        the product of (x) the Fair Market Rental Value of the Premises (as
        hereinafter defined) as of the commencement of the Extended Term,
        determined without regard to Tenant's right to extend, as agreed by the
        parties, and (y) 0.95. In no event, however, shall the Basic Rent for
        the Extended Term (which does not include Escalation Charges) be less
        than the sum of (i) $22.15 per square foot of Premises Rentable Area,
        Plus (ii) all accrued Escalation Charges payable as of the last day of
        the Initial Term. During the Extended Term, Escalation Charges shall be
        calculated using new Base Taxes and Base Operating Expenses, which shall
        be established according to the fiscal year ending June 30, 2005 and the
        calendar year ending December 31, 2004, respectively.




                                      37


<PAGE>   41


                                  ARTICLE 16
                                  ----------

                           FAIR MARKET RENTAL VALUE
                           ------------------------
  

16.1    DEFINITION. (a) The term "Fair Market Rental Value" shall mean the
        annual fixed rent that a willing tenant would pay and a willing landlord
        would accept, each acting in its own best interest and without duress,
        in an arms-length lease of the premises in question as of the date (the
        "Determination Date") on which the same is to become effective. If
        Landlord and Tenant shall fail to agree upon the Fair Market Rental
        Value within six (6) months before the Determination Date, then Landlord
        and Tenant each shall give notice (the "Determination Notice") to the
        other setting forth their respective determinations of the Fair Market
        Rental Value, and, subject to the provisions of paragraph (b) below,
        either party may apply to the American Arbitration Association or any
        successor thereto for the designation of an arbitrator satisfactory to
        both parties to render a final determination of the Fair Market Rental
        Value. The arbitrator shall be a real estate appraiser or consultant who
        shall have at least ten (10) years' continuous experience as a
        commercial real estate broker or appraiser, and having significant
        experience with property similar to the Building in the greater Boston
        area. The arbitrator shall conduct such hearings and investigations as
        the arbitrator shall deem appropriate and shall, within thirty (30) days
        after having been appointed, choose one of the determinations set forth
        in either Landlord's or Tenant's Determination Notice, and that choice
        by the arbitrator shall be binding upon Landlord and Tenant. The
        arbitrator may take into account factors such as (but not limited to)
        the then condition of the applicable space and the level of any
        leasehold improvement allowances or other inducements then normally
        being offered to prospective tenants. Each party shall pay its own
        counsel fees and expenses, if any, in connection with any arbitration
        under this paragraph (a), and the parties shall share equally all other
        expenses and fees of any such arbitration. The determination rendered in
        accordance with the provisions of this paragraph (a) shall be final and
        binding in fixing the Fair Market Rental Value. The arbitrator shall not
        have the power to add to, modify, or change any of the provisions of
        this Lease.

        (b) In the event that the determination of the Fair Market Rental Value
        set forth in the Landlord's and Tenant's Determination Notices shall
        differ by less than five percent (5%) per square foot of Premises
        Rentable Area per annum for each year for which the same is being
        determined, then the Fair Market Rental Value shall not be determined by
        arbitration, but shall instead be set by taking the average of the
        determinations set forth in Landlord's and Tenant's Determination
        Notices. Only if the determinations set forth in Landlord's and Tenant's
        Determination Notices shall differ by more than 5% per square foot of
        Premises Rentable area per annum for any year for which the same is
        being determined shall the actual determination of Fair Market Rental
        Value be made by an arbitrator as set forth in paragraph (a) above.

        (c) If for any reason the Fair Market Rental Value shall not have been
        determined prior to the Determination Date, then, until the Fair Market
        Rental Value and, accordingly, the Basic Rent, shall have been finally
        determined, Tenant shall pay Basic Rent at the rate quoted by Landlord
        in Landlord's Determination Notice. Upon final determination of the Fair
        Market Rental Value, an appropriate adjustment to the Basic Rent
        theretofore paid by Tenant from and after the Determination Date shall
        be made reflecting such final determination, and Landlord or Tenant, as
        the case may be, shall promptly credit or pay, respectively, to the
        other any overpayment of deficiency, as the case may be, in the payment
        of Basic Rent from the Determination Date to the date of such final
        determination.

                                      38


<PAGE>   42




        IN WITNESS WHEREOF, Landlord and Tenant have caused this Lease to be
duly executed, under seal, by persons hereunto duly authorized, in multiple
copies, each to be considered an original hereof, as of the date first set forth
above.


                               LANDLORD:   400/460 TOTTEN POND ROAD
                               ---------   LIMITED PARTNERSHIP

                                           By:  Leggat McCall Properties, Inc.,
                                                General Partner



                                           By: /s/ F. X. Jacoby
                                               -------------------------------
                                                Hereunto Duly Authorized



                                 TENANT:   MOLTEN METAL TECHNOLOGY, INC.
                                 -------         


                                           By: /s/ Kathy Santoro
                                               -------------------------------
                                                (Vice) President



                                           By: /s/ Benjamin T. Downs
                                               -------------------------------
                                                (Assistant) Treasurer



                                      39