抄録
A polarization modulated spectroellipsometer with time resolution of 1msec was used to analyze the dynamic response of 4-n-pentyl-4'-cyanobiphenyl(5CB) liquid orystals at the substrate surface as well as in the bulk. p-Dimethylaminoazobenzene(DAB) wags doped to monitor the dynamic behavior of 5CB molecules in the vicinity of the polyimide orienting layer using reflection ellipsometry. Compared to the results of transmission ellipsometry that monitors the behavior of bulk liquid crystals, reflection ellipsometry has much shorter relaxation time and essentially the same rise time. The fact that the rise time is same in both geometry indicates that the homogeneous-homeotropic transition occurs in a cooperative fashion. On the other hand, the difference in relaxation time indicates the presence of strong anchoring effect at the orienting layer.
