Orientational behavior of molecular liquids in restricted geometries

Subpicosecond optical birefringence techniques have been employed to probe directly the rotational dynamics of topologically different molecular liquids confined within porous sol-gel glasses. The glasses have extremely high surface areas with uniform and controllable pore diameters, allowing a systematic evaluation of the liquid behavior as a function of its geometrical confinement. Results with wetting and nonwetting liquids reveal differences between the dynamics of the surface layer and that of the bulk, thereby providing a method of calculating equilibrium properties of the adsorbed film. © 1986 The American Physical Society.