Trij? 4-n-alkil-4'-cianobifenil? termotropin?s, atspind?io ir termooptin?s savyb?s

Abstract

Investigations of temperature behaviour of the mean refractive index ne ordinary no and extraordinary ne refractive indices, and birefringence An have been carried out for three homologues of 4-n-alkyl-4'-cyanobiphenyls (n = 8, 10, 12). The principal polarizabilities ?0 and ?e, effective geometry parameter ?eg and average polarizability ?ave have been calculated using the isotropic internal field model (Vuks approach). Temperature behaviour of the order parameter in regions of the smectic A-nematic, ne-matic-isotropic liquid and smectic A-isotropic liquid is discussed. All of the optical and orientational parameters, which have been obtained in this work, are in good agreement with the theoretical approach. © Lietuvos moksl? akademija, 2015.