Methods to measure the orientational order in cholesteric liquid crystals

Abstract

The relationship between a second-rank tensor anisotropy and the orientational order in a cholesteric liquid crystal is derived. The results are confirmed by nuclear-magnetic-resonance (NMR) second-moment measurements on both the cholesteric and nematic phases of a mixture of cholesteryl chloride and $p$-azoxyanisole. The dipole NMR line shape of this sample in the cholesteric phase is explained entirely by the static cholesteric structure.