Synthesis of new photopolymeric methacrylate thioester with s-triazine ring for holographic recording

A new s-triazine containing methacrylic thioester was explored as a photofunctional monomer for holographic recording. 2-Diphenyl amino-4,6-dichloro-s-triazine derivative was prepared by the reaction of diphenyl amine and cyanuric chloride in acetone/water mixture. It further reacted with sodium hydrogen sulfide in DMF/water mixture to get the 2-diphenylamino-4,6-dithiol-s-triazine. The final dimethacrylate compound (DT) was prepared by the reaction of methacryloyl chloride with the above dithiol. Photopolymer films prepared by mixing DT with binder, aromatic acrylic monomer and photoinitiator were sensitive to a visible light and increased refractive index upon excitation with a 532 nm laser light. The optimization of holographic recording media was carried out by controlling the concentration of DT in photopolymer films to control the diffusion and polymerization. DT is crucial for high sensitivity and large refractive index change, ultimately to large diffraction efficiency (η), which are key parameters for holographic recording. A photopolymer film having optimized composition of DT showed high sensitivity and high diffraction efficiency of 98% with recording stability longer than 30 h.