Ultrasonic and viscoelastic relaxation in tri(o-tolyl) phosphate

Abstract

The velocity of propagation and attenuation of longitudinal waves have been determined for tri(o-tolyl)phosphate. The viscosity, density and shear relaxation properties of this liquid are known from previous measurements. It is found that the reduced relaxation curves for the components of the complex compressional modulus are similar to those for the corresponding components of the complex shear modulus. The relaxing part K₂ of the compressional modulus is equal to the limiting value G_∞ of the shear modulus, and the compressional viscosity η_v is 3 times the shear viscosity η. These results provide further evidence of a common origin for the compressional and shear relaxation processes.