Chiral polyesters with azobenzene moieties in the main chain, synthesis and evaluation of nonlinear optical properties

The synthesis, characterization and evaluation of nonlinear optical properties of a new series of chiral copolyesters containing push-pull electronic azobenzene mesogenic groups:in the main chain are reported. The copolyesters showed liquid crystalline behaviour with high glass transition temperatures (similar to 200 degrees C), stable liquid crystalline mesophases (up to 360 degrees C) and high second harmonic generation (SHG) efficiency. The second order nonlinear susceptibility values were measured as a function of the percentage of the chiral building' unit and the temporal stability was found to be significant over a long duration of time.