Coherence Length in the Isotropic Phase of a Room-Temperature Nematic Liquid Crystal

Abstract

The polarized ($I_{\parallel }$) and depolarized ($I_{\perp }$) scattered light intensity by fluctuations of the order parameter $Q$ near the isotropic-nematic phase transition of para-methoxybenzylidene para-$n$-butylaniline has been measured as a function of the scattering angle over a range of temperatures above the phase-transition temperature $T_p$ by means of two different incident wavelengths. Our results are in excellent agreement with the phenomenological theory of de Gennes. We also find the elastic constants $L_1\gg L_2$ while $L_1$ depends upon temperature.