Abstract
Polarized optical absorption measurements were employed to study the orientational ordering process of 4'-n-pentyl-4-cyanobiphenyl (5CB) molecules deposited by the evaporation method. 5CB molecules were evaporated onto a silica substrate with and without ultra-thin polyimide films in a laboratory ambient atmosphere. The optical absorption of the films was measured during the deposition using linearly polarized UV light. The orientational order parameter S2 was determined, even for regions of less than one monolayer thickness. The results clearly show that the orientational order is dependent on the substrate surface.