Abstract
A technique to evaluate the orientation of director of liquid crystal on the surface of thin liquid film is developed in order to examine its drying process. The drying process is quick and then the high-speed data acquisition is required. We apply the reflection polarimetry technique with the high-speed polarization state modulator. The modulated laser beam is irradiated on the surface at a certain incident angle, and the light intensity of the reflection beam is measured. The transient behaviors of the reflection rate of the S and P polarized light are evaluated simultaneously. A dried chromatic dye thin film is used as a test surface and the orientation angle is detected by the difference of the reflection rate. The change of the optical anisotropy in the drying process of a polymer liquid crystal of HPC is also evaluated using this technique.
