Second Harmonic Generation Studies of Structural Order in Langmuir-Blodgett Films

We present results of studies of oriental order of Langmuir- Boldgett monolayer and multilayer films based on second harmonic generation and linear absorption measurements. New compounds with large second order molecular susceptibilities have been synthesized and transferred as monolayers from the air-water interface to solid supports using the Langmuir-Boldgett technique. The orientational order parameters are deduced from the polarization and angular dependence of the second harmonic intensity. The dependence of second harmonic intensity on film thickness is discussed in terms of multilayer structure. Structural relaxation of the molecules has been studied by measuring linear absorption and second harmonic generation over time.