Depolarised Rayleigh scattering and textures in the nematic phase of some 4,n-alkyloxybenzoic acids

The depolarised Rayleigh scattering temperature dependence of the seventh, eighth, ninth and tenth homologues of 4,n-alkyloxybenzoic acid was investigated. A sharp increase of the scattered light intensity upon cooling was observed in the middle of the nematic phase. Polarised microscopic investigations confirmed the textural difference between the high- and low-temperature nematic regions (N 1 and N 2 ). The observed anomaly as well as the transition between classical (N 1 ) and smectic C-like (N 2 ) regions are discussed.