Photochemical and photophysical investigations on bisphenol-A-epichlorohydrin condensation polymers and model compounds

The photophysical and photochemical properties of bisphenol-A-epichlorohydrin condensation polymers and model compounds produced from aryl glycidyl ethers are attributed to the ArO— chromophore. The absorption and emission spectra, the singlet and triplet energies and also the fluorescence lifetimes of the compounds are very similar to those of aryl alkyl ethers. In solution, major photolysis products of the model compounds are phenols and substituted phenols, arising from the photorearrangement. Major photoproducts from 1,3-diphenoxy-2-propanol on irradiation at 254 nm (in N₂) differed from those at > 280 nm (in air). At low conversion, the quantum yields of compound loss are about 0·1, but the reactions are self-inhibiting, which may be attributed to light absorption and quenching by the photolysis products. Aromatic hydrocarbons with an E_s energy higher than 420 kJ mol⁻¹ sensitize the photoreactions of the model compounds. Kinetic measurements provide support for S₁-S₁ sensitization.