Optical anisotropy of some cholesteryl esters of fatty acids
Assuming the Neugebauer relations to be valid we have made calculations with regard to the effective polarizabilities and hence the optical anisotropy in smectic and cholesteric mesophases of five cholesteryl esters of fatty acids. The variation of optical anisotropy as a function of temperature and the change in optical anisotropy as we pass from the lowest temperature in the smectic phase to the lowest temperature of the cholesteric phase are correlated with the number of C-C bonds in the alkyl end groups of the molecules. It emerges that the end groups do not contribute significantly to the effective optical anisotropy owing to the existence of rotational isomerism.
KeywordsOptical anisotropy cholesteryl esters fatty acids Neugebauer relations smectic phase cholesteric phase rotational isomerism
PACS No.61·30 V
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