Dielectric relaxation in photochromically doped polymeric matrices studied by optical waveguide technique

Optical waveguide methods and, comparatively, optical absorption measurements are used to study dielectric relaxation of polystyrene (PS) thin films doped with spiropyran (SP) at optical frequencies. The time variation in the position and intensity of guided modes is connected with changes in the real and imaginary part of the dielectric function of the film at different wavelengths of the incident light, and reflects dynamic photochromic processes in the polymer matrix. The differences in the decay patterns recorded by the two methods are related to aggregate formation between colored species of the parent SP