2ND-HARMONIC GENERATION FROM FLOATING MONOLAYERS AND LANGMUIR-BLODGETT MULTILAYERS OF POLY(ISOCYANIDE)S

Floating monolayers as well as Langmuir-Blodgett (LB) films of poly(is ocyanide)s containing NLO-active side chains appear to be capable of g enerating second-harmonic light. Spin-coated films and cast films of t hese polymers do not shown this behavior. These results indicate that the NLO activity of the LB films originates from the orientation of th e side chains obtained at-the air-water interface. In the case of poly (isocyanide)s with relatively hydrophobic side chains the second-harmo nic intensities generated from the LB films are small, probably becaus e the dins are of the Y-type. Poly(isocyanide)s with more hydrophilic side chains form LB films which are Z-type. These Rims show stable sec ond-harmonic generation without the need of poling with high electrica l fields at high temperatures.