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Chelate Photochromic Material

IP.com Disclosure Number: IPCOM000073598D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Kagan, MR: AUTHOR

Abstract

This is a photochromic material comprising a combination of both organic and inorganic materials. It consists of a double doped (rare-earth or transition metals) chelate incorporated into a polymeric or similar type of host. A representative system is shown in Figure A, where a central chelated ion, M(1), is surrounded by 4, 4, 4 trifluoro-1,2-thienyl-1,3 butanedione (TTB) chelate. The whole structure is dissolved in a polymethylmethacrylate host.

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Chelate Photochromic Material

This is a photochromic material comprising a combination of both organic and inorganic materials. It consists of a double doped (rare-earth or transition metals) chelate incorporated into a polymeric or similar type of host. A representative system is shown in Figure A, where a central chelated ion, M(1), is surrounded by 4, 4, 4 trifluoro-1,2-thienyl-1,3 butanedione (TTB) chelate. The whole structure is dissolved in a polymethylmethacrylate host.

In a similar manner, one can have another metal ion, M(2), contained in the same or another chelate structure also dissolved in the same host. A photochromic reaction takes place in this material in the following manner:

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where the absorption of light at Lambda(1) removes an electron from M(1)/2+/ (- > M(1)/3+/) and transfers the electron to M(2)/3+/(-> M(2)/2+/). The resulting M(2)/2+/ ion is that which "colors" the material in this activated state. The reverse reaction occurs via the a radiation. The exact nature of the charge transfer, as is the case for most photochromic material, is not known. However, this transfer would probably take place either through the various inorganic -- organic bonds or directly by means of electron tunnelling.

Present photochromic materials are limited in their utility because of their small optical absorption cross section and their low concentration of photochromic centers. On the other hand, the optical absorption cross section of the subject chelate material is greater by many orders of magnitude. It absorbs the incident radiation Lam...