Phase Relation of p-n-Hexyloxybenzylidene-p'-toluidine (HBT) as Revealed by Thermal and Microscopic Studies

Abstract

Complex phase relation of a mesogen compound, HBT, was established by extensive DTA and microscopic texture observations. The two-step melting behavior reported previously was due to the coexistence of the two crystalline phases, Crystal I and Crystal II, which have different melting points to the nematic phase because the rate of transition between them is very slow. The conditions have been revealed under which each of the pure crystalline phases may be realized. Coexistence of the crystalline and the nematic phases is confirmed visually under a polarizing microscope at temperatures between the two melting points.