Photoisomerization quantum yields of naphthacenequinones in thin polymer films

摘要

Abstract: The influence of three effects on the behavior of photoisomerization quantum yields of organic photochromic molecules embedded into polymer matrices have been investigated by computer simulation and compared with the experimentally observed quantum yields. First, the reverse photoreaction, second, the non-uniformity of the intensity along the direction of light propagation in the sample volume due to high optical density of the medium and third, the kinetic nonequivalence of photochromic molecules. All three effects cause the decreasing of the quantum yield during reaction. The main effect causing the diminishment of quantum yield during photobleaching of 6- phenoxynaphthacenequinone is the kinetic nonequivalence of photochromic molecules in the polymer host. It is shown that the drop of quantum yield observed in this case leads to significant difficulty of erasing the information while the possible number of readout cycles is increased. The fall of quantum yield of naphthacenequinone embedded into polymer film during photocoloration is caused mainly by the reverse reaction and kinetic nonequivalence of molecules.!6