Effect of organic side-chains on the diffraction efficiency of an organic-inorganic hybrid nanocomposite film

Photopolymer nanocomposite films were prepared by dispersing an aromatic methacrylate monomer in a hybrid sol of alkoxy silanes that contained an organically modified sol-gel precursor, using the sol-gel process. Triethoxysilylpropyl, poly(ethyleneglycol)carbamate (TSPEG) was introduced to examine its effect as a side-chain in the sol-gel processed film on monomer diffusion and polymerization, to achieve holographic recording. The glass transition temperature (T_g) of the photopolymer films was shifted to a lower value as the TSPEG content was increased in the photopolymer composition. The maximum value and the evolution of the diffraction efficiency (η) of the photopolymer films under a holographic recording condition were significantly affected by the TSPEG content, indicating that the organic part of the hybrid photopolymer affected the polymerization and diffusion of the monomer during the holographic recording. Under an optimized composition (T025), the films showed a high diffraction efficiency of 0.98 under a 532nm laser with a light power of 2.1mW.