Effect of Photosensitizers on the Shrinkage Characteristics of Blue Laser Sensitive Holographic Epoxy Materials

Polymerization mechanism of epoxy material is based on ring-opening reaction, which generally results in lower shrinkage. In this study, the effect of different photosensitive dyes on the shrinkage characteristics of room temperature fast-curable epoxy polymer media for blue laser holographic recording is reported. Two photosensitive dyes, namely EB and EY dyes, for the holographic epoxy resin photopolymer material were investigated. The EB dye can induce free radical from TEA, which in turn can initiate acrylamide monomer polymerization in holographic material after irradiated by a 405 nm blue laser. The photosensitivity of dye can influence the shrinkage properties of the epoxy media after recording process. The measurement results indicate that the epoxy media addition with higher photosensitive EB dye has lower shrinkage value of about 0.25%, which is much smaller than general accepted value of about 0.5%.