Melting and Crystallization Processes of EBBA I. Thermal Analysis

Abstract

Melting and crystallization processes of EBBA (N-p-Ethoxybenzylidene-p'-butylaniline) have been studied by the method of thermal analysis and measurement of light transmittance. When the sample is cooled down from the nematic phase at a rapid cooling rate, solid phase (solid S) is formed directly. Solid S contains two solid modifications (solid S₁ and solid S₂. By heating the solid S, some amount of Solid S₁ is transformed into the nematic phase through the process of (melting of solid S₁ → crystallization to solid S₂ → melting of solid S₂). After the melting of solid S₁, some liquid crystalline state appears transiently. Solid S₁ is stabilized by the heat treatment at low temperature. The quantity of solid S₁ in solid S increases with the heat treatment time and/or with cooling at a low temperature.