Polarized UV-visible absorption spectroscopy was used to investigate the inplanc orientation of the hemicyanine molecules in Y-type Langmuir-Blodgett(LB) multilayers. We demonstated for the first time that the dipping-induced molecular alignment.was enhanced significantly with increasing the layer number due to the interlayer interactions. Polarized UV nanosecond pulses were used to control the photoinduced reorientation of the hemicyanine molecules. Thermal-isotropic process was accompaniedd by dissocition of the H-aggregate in hemicyanine LB multilayers.
