content: SECURITIES AND EXCHANGE COMMISSION
                               Washington, D.C. 20549
  
                     -------------------------------------------
  
  
                                      FORM 8-K
  
  
                                   CURRENT REPORT
  
                         PURSUANT TO SECTION 13 OR 15(d) OF
                         THE SECURITIES EXCHANGE ACT OF 1934
  
  
  
                                   Date of Report
                         (Date of earliest event reported):
  
                                  January 31, 2000
                             -------------------------
  
  
                              THERMO OPTEK CORPORATION
                           ------------------------------
                 (Exact Name of Registrant as Specified in Charter)
  
  
       Delaware                       1-11757                           04-3283973
  --------------------------------------------------------------------------------
  (State or Other Jurisdiction     (Commission File               (I.R.S. Employer
    of Incorporation)                   Number)                Identification No.)
  
  
  
  8 East Forge Parkway
  Franklin, Massachusetts                                                    02038
  --------------------------------------------------------------------------------
  (Address of Principal Executive Offices)                              (Zip Code)
  
  
         Registrant's telephone number, including area code: (781) 622-1000
  
  
  
  <PAGE>
  
  
  
  
  
           This Form 8-K contains forward-looking statements that involve a number
  of risks and uncertainties. Important factors that could cause actual results to
  differ materially from those indicated by such forward-looking statements are
  set forth under the heading "Forward-looking Statements" in Exhibit 13 to Thermo
  Optek Corporation's annual report on Form 10-K for the year ended January 2,
  1999. These include risks and uncertainties relating to: technological change,
  obsolescence, and the development and acceptance of new products; Thermo Optek
  Corporation's acquisition strategy; significant international operations;
  competition; the protection, defense and use of intellectual property;
  dependence on the semiconductor industry and industry volatility; and the
  potential impact of year 2000 on processing date-sensitive information.
  
  Item 5.  Other Events
           ------------
  
           On January 31, 2000, the Registrant issued a press release, attached
  hereto as Exhibit 99, regarding certain corporate transactions affecting the
  Registrant.
  
  Item 7.  Financial Statements, Pro Forma Financial Information and Exhibits
           ------------------------------------------------------------------
  
           (a)      Financial Statements of Business Acquired: not applicable
  
           (b)      Pro Forma Financial Information: not applicable
  
           (c)      Exhibits:
  
                    99 - Press Release dated January 31, 2000
  
  
  <PAGE>
  
  
  
                                      SIGNATURE
  
  
           Pursuant to the requirements of the Securities Exchange Act of 1934,
  the Registrant has duly caused this report to be signed on its behalf by the
  undersigned, thereunto duly authorized, on this 31st day of January, 2000.
  
  
  
                                                 THERMO OPTEK CORPORATION
  
  
                                                 By: /s/ Theo Melas-Kyriazi
                                                    -----------------------------
                                                     Theo Melas-Kyriazi
                                                     Chief Financial Officer
  
  
  
  <PAGE>
  
  
                                                                        Exhibit 99
  Investor Contact: 781-622-1111
  Media Contact: 781-622-1252
  
                          THERMO OPTEK TO BE TAKEN PRIVATE
  
  FRANKLIN, Mass., January 31, 2000 - Thermo Optek Corporation (ASE-TOC), a Thermo
  Electron company (NYSE-TMO), announced today that its parent company, Thermo
  Instrument Systems Inc. (ASE-THI), will acquire the minority interest in Thermo
  Optek for $15.00 per share in cash. This action is part of a major
  reorganization plan under which Thermo Electron will spin in, spin off, and sell
  various businesses to focus solely on its core measurement and detection
  instruments business.
  
           Thermo Instrument currently owns approximately 93.2 percent of the
  outstanding shares of Thermo Optek's common stock. Because Thermo Instrument's
  ownership is more than 90 percent, it expects to acquire the minority interest
  through a "short-form" merger in Delaware.
  
           The proposed short-form merger of Thermo Optek will require Securities
  and Exchange Commission clearance of necessary filings; it will not require
  Thermo Optek board or shareholder approval.
  
           Immediately upon completion of the proposed short-form merger, Thermo
  Optek's 5% convertible subordinated debentures due October 15, 2000, will become
  convertible into the same consideration that the minority shareholders of Thermo
  Optek common stock receive in the merger, or $15.00 per share in cash. Holders
  of the debentures will therefore have the right, immediately upon completion of
  the merger, to convert their debentures at the existing conversion price
  ($13.9446 per share) into $15.00 per share in cash, instead of into the actual
  shares of Thermo Optek common stock that they would have received if they had
  converted prior to the proposed merger. Thermo Optek will not call the
  debentures prior to the merger.
  
           Thermo Instrument expects to complete this transaction by the end of
  the second quarter of 2000.
  
           Thermo Optek Corporation is a worldwide leader in optical and
  energy-based systems and technologies. Its products are used in the scientific
  instrument, semiconductor, and telecommunications industries to fabricate,
  analyze, and implement advanced materials. More information is available on the
  Internet at http://www.thermo.com/subsid/toc1.html.
  
  The following constitutes a "Safe Harbor" statement under the Private Securities
  Litigation Reform Act of 1995: This press release contains forward-looking
  statements that involve a number of risks and uncertainties. Important factors
  that could cause actual results to differ materially from those indicated by
  such forward-looking statements are set forth under the heading "Forward-looking
  Statements" in Exhibit 13 to the company's annual report on Form 10-K for the
  year ended January 2, 1999. These include risks and uncertainties relating to:
  technological change, obsolescence, and the development and acceptance of new
  products; the company's acquisition strategy; significant international
  operations; competition; the protection, defense, and use of intellectual
  property; dependence on the semiconductor industry and industry volatility; and
  the potential impact of year 2000 on processing date-sensitive information.
metadata_documents: [{"type": "8-K", "sequence": "1", "description": "FORM 8-K", "secsgml_size_bytes": 6852}]
metadata_filer: {"company-data": {"conformed-name": "THERMO OPTEK CORP", "cik": "0001012368", "assigned-sic": "3826", "irs-number": "043283973", "state-of-incorporation": "DE", "fiscal-year-end": "0102"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-11757", "film-number": "519301"}, "business-address": {"street1": "8 E FORGE PARKWAY", "street2": "P.O. BOX 9046", "city": "FRANKLIN", "state": "MA", "zip": "02038", "phone": "6176221000"}, "mail-address": {"street1": "81 WALTHAM STREET", "street2": "P.O. BOX 9046", "city": "WALTHAM", "state": "MA", "zip": "02154"}}
text: SECURITIES AND EXCHANGE COMMISSION
                               Washington, D.C. 20549
  
                     -------------------------------------------
  
                                      FORM 8-K
  
                                   CURRENT REPORT
  
                         PURSUANT TO SECTION 13 OR 15(d) OF
                         THE SECURITIES EXCHANGE ACT OF 1934
  
                                   Date of Report
                         (Date of earliest event reported):
  
                                  January 31, 2000
                             -------------------------
  
                              THERMO OPTEK CORPORATION
                           ------------------------------
                 (Exact Name of Registrant as Specified in Charter)
  
       Delaware                       1-11757                           04-3283973
  --------------------------------------------------------------------------------
  (State or Other Jurisdiction     (Commission File               (I.R.S. Employer
    of Incorporation)                   Number)                Identification No.)
  
  8 East Forge Parkway
  Franklin, Massachusetts                                                    02038
  --------------------------------------------------------------------------------
  (Address of Principal Executive Offices)                              (Zip Code)
  
         Registrant's telephone number, including area code: (781) 622-1000
  This Form 8-K contains forward-looking statements that involve a number
  of risks and uncertainties. Important factors that could cause actual results to
  differ materially from those indicated by such forward-looking statements are
  set forth under the heading "Forward-looking Statements" in Exhibit 13 to Thermo
  Optek Corporation's annual report on Form 10-K for the year ended January 2,
  1999. These include risks and uncertainties relating to: technological change,
  obsolescence, and the development and acceptance of new products; Thermo Optek
  Corporation's acquisition strategy; significant international operations;
  competition; the protection, defense and use of intellectual property;
  dependence on the semiconductor industry and industry volatility; and the
  potential impact of year 2000 on processing date-sensitive information.
  
  Item 5.  Other Events
           ------------
  
           On January 31, 2000, the Registrant issued a press release, attached
  hereto as Exhibit 99, regarding certain corporate transactions affecting the
  Registrant.
  
  Item 7.  Financial Statements, Pro Forma Financial Information and Exhibits
           ------------------------------------------------------------------
  
           (a)      Financial Statements of Business Acquired: not applicable
  
           (b)      Pro Forma Financial Information: not applicable
  
           (c)      Exhibits:
  
                    99 - Press Release dated January 31, 2000
  SIGNATURE
  
           Pursuant to the requirements of the Securities Exchange Act of 1934,
  the Registrant has duly caused this report to be signed on its behalf by the
  undersigned, thereunto duly authorized, on this 31st day of January, 2000.
  
                                                 THERMO OPTEK CORPORATION
  
                                                 By: /s/ Theo Melas-Kyriazi
                                                    -----------------------------
                                                     Theo Melas-Kyriazi
                                                     Chief Financial Officer
  Exhibit 99
  Investor Contact: 781-622-1111
  Media Contact: 781-622-1252
  
                          THERMO OPTEK TO BE TAKEN PRIVATE
  
  FRANKLIN, Mass., January 31, 2000 - Thermo Optek Corporation (ASE-TOC), a Thermo
  Electron company (NYSE-TMO), announced today that its parent company, Thermo
  Instrument Systems Inc. (ASE-THI), will acquire the minority interest in Thermo
  Optek for $15.00 per share in cash. This action is part of a major
  reorganization plan under which Thermo Electron will spin in, spin off, and sell
  various businesses to focus solely on its core measurement and detection
  instruments business.
  
           Thermo Instrument currently owns approximately 93.2 percent of the
  outstanding shares of Thermo Optek's common stock. Because Thermo Instrument's
  ownership is more than 90 percent, it expects to acquire the minority interest
  through a "short-form" merger in Delaware.
  
           The proposed short-form merger of Thermo Optek will require Securities
  and Exchange Commission clearance of necessary filings; it will not require
  Thermo Optek board or shareholder approval.
  
           Immediately upon completion of the proposed short-form merger, Thermo
  Optek's 5% convertible subordinated debentures due October 15, 2000, will become
  convertible into the same consideration that the minority shareholders of Thermo
  Optek common stock receive in the merger, or $15.00 per share in cash. Holders
  of the debentures will therefore have the right, immediately upon completion of
  the merger, to convert their debentures at the existing conversion price
  ($13.9446 per share) into $15.00 per share in cash, instead of into the actual
  shares of Thermo Optek common stock that they would have received if they had
  converted prior to the proposed merger. Thermo Optek will not call the
  debentures prior to the merger.
  
           Thermo Instrument expects to complete this transaction by the end of
  the second quarter of 2000.
  
           Thermo Optek Corporation is a worldwide leader in optical and
  energy-based systems and technologies. Its products are used in the scientific
  instrument, semiconductor, and telecommunications industries to fabricate,
  analyze, and implement advanced materials. More information is available on the
  Internet at http://www.thermo.com/subsid/toc1.html.
  
  The following constitutes a "Safe Harbor" statement under the Private Securities
  Litigation Reform Act of 1995: This press release contains forward-looking
  statements that involve a number of risks and uncertainties. Important factors
  that could cause actual results to differ materially from those indicated by
  such forward-looking statements are set forth under the heading "Forward-looking
  Statements" in Exhibit 13 to the company's annual report on Form 10-K for the
  year ended January 2, 1999. These include risks and uncertainties relating to:
  technological change, obsolescence, and the development and acceptance of new
  products; the company's acquisition strategy; significant international
  operations; competition; the protection, defense, and use of intellectual
  property; dependence on the semiconductor industry and industry volatility; and
  the potential impact of year 2000 on processing date-sensitive information.