Evidence for the Participation of Singlet Oxygen in the Vat-dye Photosensitized Degradation of Cellulose

A study has been made of the vat-dye photosensitized degradation of cellulose. Whilst die part played by the dyes in direct hydrogen abstraction from a cellulose substrate cannot be overlooked, it is apparent that the role played by singlet oxygen is important. The ability of a dye to produce singlet oxygen has been studied by measuring die amount of tetraphenylcyclopentadienone the dye can photooxidize. Luminescence spectroscopy has been employed in order to gain information about the excited state energies of the dye molecules, and an electron spin resonance study of die dyes in rigid media has been carried out in order to obtain information about die triplet state