Phase Transition Studies of the Liquid Crystal Pentyloxybenzylidene Phenylazoaniline

Phase transition studies of the liquid crystal pentyloxybenzylidene phenylazoaniline are investigated with density and ultrasonic velocity measurements. The density variation with temperature confirms that the isotropic liquid‐nematic, nematic‐smectic A and smectic A‐smectic B transitions are of first order. The temperature variation of ultrasonic velocity confirms all the phase transitions. The adiabatic compressibility (βad), Rao number (Rn) and Molar compressibility (B) are estimated from density and ultrasonic velocity.