The optical anisotropy and orientational order parameter of two mesogens having slightly different flexible side chain – a comparative study

ABSTRACT

Variation of the phase transition temperatures and existence of different number of mesophases, due to the changes of -CH₂ groups at the oxygen containing flexible side chain between two Schiff’s base liquid crystals compounds p-ethoxybenzylidine p-heptylaniline (EBHA) and p-butoxybenzylidine p-heptylaniline (BBHA) have been studied by using POM and DSC. Refractive indices as a function of temperature of these two compounds have also been measured by the well-known thin prism technique. To get the best accuracy of refractive indices data a comparison between the experimental data and theoretical values which are obtained from modified four-parameter model based on Vuks’ hypothesis have been done. A comparative study of some important parameters such as, optical anisotropy, orientational order parameters of these two liquid crystal compounds have also been conducted.

Graphical Abstract

KEYWORDS:

• Liquid crystal
• mesophase texture
• birefringence
• four parameter
• order parameter

Acknowledgement

Authors express thanks to Dr S. K. Das. HOD of chemistry department, NIT, Agartala, for providing them facility to perform DSC study in his departmental laboratory.

Disclosure statement

No potential conflict of interest was reported by the authors.