Analysis of the absorptive behavior of photopolymer materials. Part I. Theoretical modeling

Photopolymers have received a great deal of attention due to their broad range of applications. The variation of their absorptive behavior during exposure is pivotal to the study of such materials. A model combining the associated electromagnetics and photochemical kinetics is presented to describe these absorptive processes. Such a model is critical in describing both self-modulations during holographic recording and also self-focusing effects. To describe the photophysical and photochemical changes taking place, a modulated equivalent electrical conductivity is introduced. Temporal variations of the concentrations of dye, monomer, and polymer are then predicted using the modified nonlocal photopolymerization driven diffusion model. The numerical convergence of the model is examined. Comparisons between the predictions of the model and experimental results, for both acrylamide/polyvinyl alcohol and Phenanthrenequinone doped poly(methyl methacrylate) photopolymer materials, are presented and analyzed in Part II of this paper.