The inter-molecular interactions, intra-molecular interactions, structural properties and physiochemical behaviour can be explained by knowing the thermo-physical properties of the polymer–solvent mixture. In the present research work, these properties have been studied by using an ultrasonic interferometer by measuring the sound velocity in the mixture of polymer and solvent. With the in-depth knowledge of molecular interactions, the physical properties of these ferroelectric polymers have been explained at a deeper level. In our experimental investigation the polymer, PMMA (polymethyl methacrylate) is used. The mixture is prepared by dissolving the polymer in acetone. Ultrasonic waves of frequency 5 MHz via ultrasonic interferometer is passed through the polymer–solvent mixture of different (w/v) percentage at 2 %, 4 %, 6 %, 8 % & 10 % at various temperatures 308 K, 313 K, 318 K, 323 K, 328 K, & 333 K and ultrasonic wave velocity is measured. The acoustical parameters such as ultrasonic attenuation, adiabatic compressibility, relaxation time, & acoustic impedance have been calculated using the ultrasonic wave velocity. The experimental observations are discussed in detail.