Bulletin of the Chemical Society of Japan · 1995 · 42 citations · 7 references
Natural SciencesChemistryMaterials ScienceOptical MaterialsOrganic ChemistryPolymer ChemistryFatigueOptical PolymersPhotochemical KineticsPhotochemistryPhotochromic MaterialsPolymer DegradationLight ExposureLight-induced DegradationPhotolysisPhotolysis ProcessesPhotooxidationPhotosensitizing CompoundsPhotostationary StateSpirooxazine Compounds
Abstract Photochromic polyurethane films containing 5-substituted 1,3-dihydro-3,3-dimethyl-1-alkylspiro[2H-indole-2,3′-[3H]pyrido[3,2-f][1,4]benzoxazine] and 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]naphth[2,1-b][1,4]oxazine] were degraded under xenon light exposure. The loss of the photochromic response was monitored by spectrophotometry as a function of the irradiation time; meanwhile, the photoproduct formation and the amount of photochromic material still available were analyzed by chromatography after liquid–solid extraction. At the same time, the fade rates were monitored after flash-excitation photolysis or after the photostationary state during degradation. It was clearly demonstrated that the loss of photochromism was due exclusively to a photooxidation process of the initial dye, and not to an acceleration of the bleaching or a potential screen effect caused by the photoproducts.
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Oxidative degradation of organic photochromes
V. Malatesta, Mario Milosa, Roberto Millini et al. · Molecular crystals and liquid crystals science technology. Section A, Molecular crystals and liquid crystals/Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals · 1994 · 41 citations