摘要：

The polymer structural effects on light-induced molecular movement below the glass transition temperature (Tg) of very high Tg (up to 350°C) polyimide polymers containing nonlinear optical azo chromophores are discussed. It is shown to what extent the isomerization reaction itself and the light-induced nonpolar and polar orientation depend on the molecular structure of the unit building blocks of the polymer. We demonstrate photo-induced orientation of azo chromophores in these polyimides at room temperature even though the chromophore is firmly embedded into the rigid polymer backbone, and how Light can alter the optical third-order nonlinearity by changing the chromophore hyperpolarizability through a photo-induced isomer change in shape.

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