Optical measurements of phase transitions in difluorophenylazophenyl benzoate thermotropic liquid crystal with specific orientated fluorine atoms

ABSTRACT

Phase transition temperature and optical properties of the special oriented fluorine atoms in difluorophenylazophenyl Benzoate Thermotropic Liquid Crystal nominated (III) were studied and measured. Absorbance and transmittance in the visible region at room temperature for the compound III dissolved in methylene chloride of different concentrations were determined. The maximum absorbance for the compound III was in the blue region (447 nm) and the molar absorption coefficient was found to be 0.93 (L. mMol⁻¹.cm⁻¹). The transition temperature was determined for the thermotropic LC compound III by using DSC, POM and modified spectrophotometer techniques. Nematic and smectic phases during the cooling process were observed. Ordinary and extraordinary refractive indices, birefringence, order parameter and the molecular polarizability were determined with different temperatures for the LC phases of compound III.

KEYWORDS:

• Phase transition
• optical parameters
• modified spectrophotometer
• refractive index
• birefringence
• order parameter

Acknowledgements

I wish to express my sincere thanks to assistant Prof. Dr H. A. AHMED Chemistry Department, Faculty of Science, Cairo University and assistant Prof. Dr Mohamed Hagar, Alex University for their facilities.

Disclosure statement

No potential conflict of interest was reported by the author.