Motional and Relaxational Processes in Amorphous and Crystalline Phases of Methoxybenzylidene-butylaniline II. Raman Spectroscopy of MBBA in its Solid and Nematic Phases

Abstract

Raman spectra for 4-methoxybenzylidene-4′-butylaniline (MBBA) in its nematic liquid crystal phase and in all its solid phases were measured in the frequency range 5–1700 cm⁻¹. Clear modifications have been observed at the phase transitions, not only in the low frequency range, but also in the internal vibrational modes. Different stages of the structural order in the successive polymorphic modifications are evidenced. In addition, the changes which occur in the intramolecular part of the spectra reveal that phase transitions directly affect the butyl tail while others are related to conformational modifications of the core of the molecule.