Infrared Spectroscopic Measurements on the Crystal-Nematic Transition

Abstract

Although many studies have been carried out to measure the extent of order as a function of temperature in the liquid crystalline state of thermotropic liquid crystals, little work has been done to indicate the amount of order or disorder in solids as the liquid crystalline state is approached. Such studies as have been reported (1), mainly deductions based on the shape of thermal analysis curves in the pre transition region, indicate that the crystal-nematic transition maybe of greater than first order or that there maybe some pre-transition phenomena. The shapes of DTA and DSC curves are, however, very dependent on instrumental response, etc., often in ways which have yet to be fully explored.