摘要：

We quantified coupled photoisomerization and photoorientation of a diarylethene-type chromophore in films of poly(methyl methacrylate). We found that the chromophore retains partial memory of its orientation during the A → B UV-induced isomerization and that the chromophore movement is thermalized after the A←B green light induced isomerization. The isomerization quantum yields are = 1.1, = 0.32, and = 0.16, and the transitions at 365 (405) and 532 nm of the B isomer are oriented at an angle of 74.3 (61.3)° to each other. This relative orientation of the transition dipoles is rationalized by MOPAC molecular orbital calculations.

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