摘要：

We show that the occurrence of pure photoorientation by photoisomerization of azo dye in polymers is influenced by the polymer molecular structure, as well as by the photoisomerization quantum yields and the cis → trans thermal isomerization rate. These findings are rationalized by the study of the photoorientation of azo dye in a series of polyurethane polymers, each with distinct differences in the molecular structure of the unit building blocks. It will be shown that the thermally activated chromophore movement in these polymers is dictated by the polymer backbone. We also show how to quantify coupled photoisomerization and photoorientation of spectrally overlapping isomers in polymers, and we determine the photoisomerization quantum yields and the photoorientation movement of the chromophores in azo-polyurethanes.

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