Optical Tracers of Polymer Phase Transitions

Abstract

Phthalocyanine and quinacridone pigments have been used in a variety of photovoltaic devices [1]. These pigments find utility as photoreceptors in xerography, photoelectrochemical devices and model solar cells [2]. They are of particular interest because of their high absorption in the visible region of the electromagnetic spectrum and their inherent chemical and thermal stability [3]. Asymmetric quinacridones demonstrate significant NLO properties. In recent years, devices based on quinacridones have shown great promise. In a few of these applications thin films of quinacridones, prepared by vacuum sublimation, are deposited onto electrode materials, however, in almost all other applications, the insoluble pigment is dispersed in a polymer binder at relatively high concentration [4]. Polymeric binders include polycarbonates and polyalkylmethacrylates [5].