2ND-HARMONIC GENERATION IN A NOVEL CROSS-LINKED PYROELECTRIC LIQUID-CRYSTAL POLYMER (PLCP)

We report second-harmonic generation in samples with a pyroelectric li quid crystal polymer (PLCP) prepared from the ferroelectric liquid cry stalline acrylate monomer [(R)-(-)-2-(10-acryloyloxydecyl)oxy]-3-nitro phenyl 4-[4-(11-acryloyloxyundecyloxy)phenyl]-benzoate (A2c) by in sit u photopolymerization. The relation between SHG efficiency, spontaneou s polarization and amount of chiral substance in this and previously s ynthesized PLCP materials is discussed. Electro-optical properties of the monomeric and crosslinked A2c are investigated. In the crosslinked state, the molecular mobility is found to be very low, supporting the fact that the degree of polar order in the polymer is high. In contra st to the case of a poled electret NLO material, the polarization of t his material is not 'frozen-in', but an intrinsic thermodynamic proper ty.