Proton NMR Measurements of Liquid Crystals Whose Nematic Range Has Been Extended by Supercooling

Abstract

The proton spin lattice relaxation time was measured as a function of temperature over an extended nematic range for $p$-methoxybenzylidene aminophenylacetate and $p$-azoxydianisole by supercooling. The results show that the relaxation rate varies exponentially with reciprocal temperature in a manner similar to that in $p$-methoxybenzylidene butylaniline and ethoxybenzylidene butylaniline. The results are interpreted in terms of the Doane, Tarr, and Nickerson model of relaxation in nematic mesophases.