Accession Number : ADA336810

Title :   Photodeposition in Glasses

Descriptive Note : Final rept. 1 Apr 94-31 Mar 97

Corporate Author : QUEENS COLL FLUSHING NY CHEMISTRY DEPT

Personal Author(s) : Gafney, Harry D.

PDF Url : ADA336810

Report Date : 05 JAN 1998

Pagination or Media Count : 9

Abstract : Changes in refractive index achieved by photodeposition and their transmissivity depend on the nature of the material deposited, its aggregation and its effect on the host matrix. 254-nm photolysis of (CH3)3SnI chemisorbed onto porous Vycor glass and Si-based sol-gel glasses leads to homolytic cleavage of the Sn-I bond. Depending on medium polarity, a fraction of the radical pairs thermalize via electron transfer and (CH3)3Sn(+), which is converted to SnO2 during the subsequent annealling, changes the refractive index. During consolidation, Sn and/or SnO displace boron from the matrix, and the corresponding change in glass composition opens a 100-150 deg C window that has been exploited to introduce reagents that are unable to withstand glass processing temperature into an optical network in glass. Ferromagnetic impregnates exhibiting extremely high coercivity obtained by photolysis of Fe(CO)3 have been shown to be 100 Angstrom diameter particles of alpha-Fe2O3, where particle size is determined principally by the initial pore size of the class. A technique has been developed to pattern micron-resolution, transparent, electrically conductive regions on porous glasses without significant reductions in glass porosity. During the course of these experiments, a new type excited-state coordination chemistry has been discovered.

Descriptors :   *PHOTOCHEMICAL REACTIONS, *GLASS, PARTICLE SIZE, REFRACTIVE INDEX, ELECTRICAL CONDUCTIVITY, POROSITY, DEPOSITION, POLARITY, TRANSMISSIVITY.

Subject Categories : Radiation and Nuclear Chemistry
      Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE