MECHANISMS OF FRONT PROPAGATION OF PHOTOCHEMICAL-REACTIONS IN POLYMERCONTAINING MEDIA .1. FRONTAL REGIMES OF PHOTOCHEMICAL-REACTIONS IN POLYMER MATRICES WITH BLEACHING OF SPECIMEN BEHIND THE FRONT

The propagation of conversion fronts and their forms are experimentall y revealed by 9,10-diphenyl anthracene photo-oxidation in butyl methac rylate/methacrylic acid copolymer films, as an example. In addition to the absolute bleaching regime the partially bleached one was analysed and investigated. The latter case was realized by the addition of a u .v. -absorber-5-chloro-2-(2' ydroxy-5'-methyl-3-tert-butylphenyl)benzo triazole. The method of allowing for light losses under routine photoc hemical experiments with non-rigorous parallel light beams was suggest ed. This method was used for a quantitative description of front propa gation kinetics. Copyright (C) 1996 Elsevier Science Ltd.