Photopolymerization model for holographic gratings formation in photopolymers

This work describes the study of free-radical homopolymerization kinetics for a system based on acrylamide, triethanolamine, and methylene blue on a polyvinylalcohol matrix, by analyzing temporal variations of the diffraction efficiency. Due to the high viscosity of the material, it has been demonstrated that diffusion processes at the time of recording are negligible. So, the modulation index has been related to the parameters of the systems components, giving as a result, a method that can be used to estimate the chain-length of the polymer, the kinetic rate constants and absorption-scattering parameters. Depending on the termination step, two models of homopolymerization has been proposed – a bimolecular model (bimolecular termination) and a radicalic model (primary radical termination). Using these methods it was possible to compare the results obtained for the kinetic parameters of the photopolymerization process when the intensity and the concentration of each component were changed. Thus, holography can be used as holographic method to analyze the photopolymerization processes. PACS 42.70.Ln; 42.70.Jk; 42.40.Ht