Bifunctional cyclosiloxanes with photorefractive properties

A series of novel bifunctional cyclosiloxanes with pendant photoconducting and nonlinear-optical moieties was synthesized in a two step procedure. The variation of the spacer length between the siloxane ring and the functional carbazole and azo moieties leads to glass transition temperatures between 33 degrees C and 61 degrees C. These well defined low-molar mass compounds are characterized with regard to their chemical, thermal and electrooptical properties. Compared to commonly used guest-host systems crystallization of the chromophore dopants is diminished due to the covalent bonding of the azo-dye to the cyclosiloxane backbone.