Photoinduced Absorption and Erasable Optical Information Storage in Polyanilines

Abstract Photoinduced absorption spectroscopy has been used to study a variety of forms of polyaniline. Experiments on emeraldine base and leucoemeraldine base have led to a picture of the photoproduction and decay of massive, long-lived defect states that can be described in terms of conformational changes involving rotations of the C 6 H 4 rings. Photoexcitation spectra of other polyanilines, such as pernigraniline base and poly( o -toluidine), exhibit similar features including relatively weak photoinduced infrared vibrations and a relatively strong photoinduced absorption peak near 1.4–1.5 eV. In several of these materials, the photoinduced changes are very long-lived, leading to an investigation of the polyanilines as media for erasable optical information storage.