This paper presents the results of experimental studies of the optical recording and thermal amplification of phase gratings in a new polymeric composite with diffusion amplification, based on PMMA and benzophenone. The phase gratings were recorded by exposing layers to incoherent UV radiation (365 nm) through an amplitude mask and an interference pattern formed by the radiation of a pulsed Nd: YAG laser (355 nm). Post-exposure heat treatment of the layers resulted in amplification of the gratings. The kinetics of the process are consistent with concepts of the diffusion nature of the amplification. The photo- and thermostability of the gratings after amplification made it possible to conclude that photoattachment of the benzophenone to the PMMA occurs in the layers, resulting in diffusion relaxation of the inhomogeneous distribution of the benzophenone concentration. Refractive-index modulation of 1.6 × 10 ~(-3) was achieved for PMMA layers containing benzophenone with a mole fraction of 2.
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