Measurement principle and method for liquid crystal's rotational viscosity coefficient

Rotational viscosity is one of important liquid crystal s physical properties for display and telecommunication industries. The measurement method and principle of the temperature dependence of rotational viscosity coefficient of nematic liquid crystal were investigated on a personal computer-based optical system developed by us. Rotational viscosity coefficient was calculated from the phase decay time tested on the optical system. The data of the temperature dependence of rotational viscosity coefficient of a typical LC material-a Merck nematic E7 mixture were given, and experimental results agree with the theory well, which verifies the correction of the principle. The method is simple and automatic.