Electro-optic properties of a bi-chromophore norbornene polymer brush system

A selection of poly(norbornene-exo-dicarboximide) brush-type polymers decorated with a pendent azobenzene dye have been prepared for use as electro-optic (EO) hosts. These polymer brushes were employed as EO polymer hosts for a high molecular hyperpolarizability phenyl vinylene thiophene vinylene (FTC) chromophore guest. These polymer brushes contained methoxy or cyano azobenzene substituents, which were able to manipulate the p-electronic polarization, refractive index, and EO activity. The concentration of the azobenzene dye was increased from 6 to 38%, in order to find the optimum and to maximise the EO coefficient. The refractive index of the mixtures could also be tuned by changing the azobenzene content. Ultimately an EO coefficient of nearly 95pm/V could be realized using a methoxy substituted azobenzene brush at a concentration of 25% with an added FTC chromophore.