Kinetics of decolorization of spironaphthooxazine-doped photochromic polymer films.

Photochromic polymeric films were prepared by doping photochromic dye spironaphthooxazine into polymer resin gels such as polyurethane, vinyl copolymer, and copolymer of vinyl and nitorocellulose at different concentrations. All of the composite films show normal photochromism. The kinetics of the photochromism/decoloration in the films were quantified by fitting biexponential equations to their photochromic decay curves after irradiation. It was observed that the decoration process is faster in vinyl copolymer than that in the copolymer of vinyl and nitrocellulose and is the slowest in the case of polyurethane. The decoloration mechanisms of spironaphthooxazine in those polymeric matrixes have been discussed.