Molecular Organisation in the Smectic Mesophase of Ethyl 4-azoxybenzoate

Abstract

Abstract The static and dynamic properties of the nematic mesophase have been studied in numerous electron resonance experiments. Similar studies of the smectic mesophase are much rarer.(1,2,3) In these experiments the smectic phase had been oriented by cooling the preceding nematic mesophase, aligned by a magnetic field, to a temperature below the nematic-smectic transition point. Even if the mesogen does not possess a nematic phase it has been claimed(4) that an oriented smectic mesophase can be obtained by cooling the isotropic melt in the presence of a magnetic field. This claim is supported by a recent nuclear magnetic resonance experiment(5) although the high solute concentration may mean that this behaviour is not characteristic of the pure smectogen. We had hoped therfore to use this technique to align the smectic mesophase of ethyl 4-azoxybenzoate which does not possess a nematic mesophase. As we shall see these expectations were not completely realised although the mesophase was aligned by an al...