Photochromism of diarylethene derivatives in rigid polymer matrix: structural dependence, matrix effect, and kinetics

Photochromic reactions of three diarylethene derivatives embedded in three types of polymer matrices were studied using a variety of spectroscopic techniques and quantum ab initio computations. It was found that the photochromic efficiencies of diarylethene molecules depend on the structural and electronic characteristics of Franck-Condon region in the excited states, and also depend strongly on the sizes of free inner spaces of the matrices. The steady-state and time-resolved fluorescence studies revealed the detailed kinetics of the planar and twisted conformers in the excited states, The observed fluorescence lifetimes of the planar and twisted conformers were similar to 2.6 ns and 8 similar to 30 ns. (C) 2000 Published by Elsevier Science B.V.