Examination of the photoinitiation processes in photopolymer materials

Abstract

Photopolymer materials are practical materials for use as holographic recording media. In order to further develop such materials, a deeper understanding of the photochemical mechanisms present during the formation of holographic gratings in these materials has become ever more crucial. This is especially true of the photoinitiation process, which has already received much attention in the literature. Typically the absorption mechanism varies with exposure time. This has previously been investigated in association with several effects taking place during recording. Since holographic data storage requires multiple short exposures, it is necessary to verify the temporal change in photosensitizer concentration. Post exposure effects have also been discussed in the literature; however, they do not include post exposure effects such as the photosensitizer recovery. In this paper we report experimental results and theoretical analysis to examine the effects of the recovery and bleaching mechanisms which arise during exposure.