AZOMETHINES WITH NONLINEAR-OPTICAL PROPERTIES AND POLYESTERS COVALENTLY FUNCTIONALIZED WITH THEM - SYNTHESES WITH NITRILES IC

Polyesters with covalently bound azomethine and carbonanalogous dye mo ieties were obtained by polymer analogous reactions. Their nonlinear o ptical properties were examined by electric field induced second harmo nic generation measurements and compared with corresponding monomeric dyes. All of them had maximum absorption wavelengths between 400 and 5 46 nm. Values for mu beta (dipole moment mu, molecular hyperpolarizabi lity beta) reached 290x10(-68) Cm-5/V. Quantum chemical calculations i ndicate the existence of various conformers of the dyes with large dif ferences in their nonlinear optical properties. Furthermore, the calcu lations also point to a profound sensitivity of the molecular hyperpol arizability to environmental (solvent) effects amounting to an order o f magnitude. (C) 1997 Elsevier Science Ltd.