BULK REORIENTATION DRIVEN BY ORIENTATIONAL TRANSITION IN A LIQUID-CRYSTAL MONOLAYER

Optical second-harmonic generation has been used to study the effect o f coadsorbed small volatile molecules on the orientational order of a liquid crystal monolayer at the interface between a mica surface and a liquid crystal film. As the chemical potential of the volatile molecu les was increased, a first-order orientational transition was observed in the monolayer. This surface transition is shown to drive the reori entation of the bulk liquid crystal previously observed in these syste ms.