PHOTOCHROMISM AND ITS MECHANISM IN POLYDIACETYLENE CRYSTALS

Based on summarizing and analyzing experimental facts of photochromism in polydiacetylene crystals, a theoretical model describing the photochromic process was presented. It is considered that the photochromism is the result of phase structural conversion during photoexcitation excitonic relaxation process, and its dependence on the energy and density of incident photons can be explained correctly. The micro-mechanism of photochromism is discussed in detail.