Polyamic alkyl ester system promising for side-chain electro-optic polymer

A polyamic alkyl ester was examined for the first time as a new candidate for an electro-optic (EO) polymer. Disperse Red 1 was easily introduced into a polyamic acid synthesized from 2,2-bis(4-aminophenyl)hexafluoropropane and oxydiphthalic anhydride by the Mitsunobu reaction. The EO polyamic alkyl ester film is amorphous. The dipole orientation in the film is slightly aligned without a poling process, showing ∼5 pm/V. The best poling temperature is ca. 145 °C with regard to a rearrangement of the EO polyamic alkyl ester into the corresponding polyimide. The EO coefficient of the poled film is around 25 pm/V at a wavelength of 1.55 μm when the film is poled with an applied voltage of 150 V/μm. The EO signal is thermostable.