Acoustooptical parameters in a mixture of polyvinyl alcohol (PVA) polymers with modified polyvinyl alcohol (MPA) were investigated as functions of the MPA content, time of exposure and temperature. The maximum value of the acoustooptical quality coefficient was achieved for values of the MPA content above 70%. It was proposed to use the polyvinyl alcohol photopolymers as acoustooptical modulators and deflectors. An essential influence of the polyvinyl alcohol modifications on the acoustooptical parameters was unambiguously shown. Also, a critical dependence of the acoustooptical coefficients on the sample thickness was revealed. The data on the acoustooptical quality coefficient correlate well with the data obtained for the sound losses coefficient.