The dynamics of the electrooptic and dielectric properties in low-Tg photorefractive guest-host polymers are directly related to the orientational dynamics of doping nonlinear optical chromophores. We report on experimental results on the orientational mechanisms of chromophores above Tg, investigated by ellipsometry and dielectric spectroscopy. These measurements have been performed on plasticized poly(N-vinylcarbazole) and polysiloxane functionalized with a carbazole pendant, doped with nonlinear optical chromophores. The data are compared to the mechanically measured complex shear compliance of the materials. The results of this comparison demonstrate that the orientational dynamics of chromophores are entirely ruled by the viscoelastic properties of the polymer matrix. In addition, the influence of the chromophore size is investigated and interpreted by using free volume and rheological laws. Finally, the evidence of an anelastic memory, induced by the orientation of the chromophores below Tg, is pointed out.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry