Synthesis and characterisation of 1,3-bis(dicyanomethylidene)indane (BDMI)-based nonlinear optical polymers

New polymers containing nonlinear optical chromophores of electron donor-bridge moieties amino-phenylenethienylidene (APT) coupled with a strong electron acceptor 1,3-bis(dicyanomethylidene)indane (BDMI) were synthesised by coupling the aldehydic APT precursor polymers with acceptor BDMI in acetic anhydride. The aldehydic APT precursor polymers were prepared via traditional condensation or radical polymerisation schemes where the aldehydic group of APT was found intact. Thermal stability of these BDMI-based polymers determined by t.g.a. was up to 500°C depending mainly on the chromophore loading density. The electro-optic coefficient ( r 33 ) of 10 pm V −1 was obtained in a 30% by weight chromophore loading polymer.