X-ray diffraction analysis of the structure of MBBA solid phases

Abstract

The nematic liquid crystal compound MBBA exhibits a large number of solid phases, e.g., on fast cooling a glassy state may be formed, four metastable phases are obtainable by annealing. Since the sample relaxes by increasing the annealing temperature, the structure of the phases becomes less and less symmetric. X-ray diffraction measurements were performed to characterize the phase structure of non-aligned samples using a position sensitive x-ray camera. A data treatment procedure was elaborated to derive quantitative features of the diffraction patterns. The solid smectic structure of the non-completely-ordered phases are characterized.