Studies of Photosensitive Resins. IV. Photosensitization Mechanism of Polyvinyl Cinnamate

Abstract

Abstract The photosensitization mechanism of polyvinyl cinnamate was investigated by measuring the phosphorescence spectra of cinnamic acid and sensitizers. The peak of phosphorescence for trans-cinnamic acid was found to be 20100 cm−1, and the triplet energies of the effective sensitizers were found to be situated near or higher than that of cinnamic acid. It was established that the phosphorescences of sensitizers were exceedingly quenched when cinnamic acid was introduced into their solutions. This finding can be understood if it is assumed that the excitation energy is transferred from the triplet state of the sensitizer to that of cinnamic acid. The critical separation of donor and acceptor and the configuration of the triplet state for cinnamic acid are also discussed.