TBA Studies of Viscoelastic Behavior of Some Glass-Forming Liquids

Abstract

The viscoelasticity of some glass-forming liquids was studied by means of the torsional braid analysis (TBA) which consists of measurements of storage and loss elastance in torsional oscillation on a glass braid saturated with a test liquid. The measurements were made along two different paths of temperature variation, slow cooling from room temperature to liquid nitrogen temperature and slow heating from the latter attained by rapid cooling.
Tricresyl phosphate and dibutyl sebacate showed only one dispersion corresponding to glass transition and crystallization, respectively. Dimethyl phthalate and dioctyl phthalate showed one dispersion corresponding to crystallization in the slow cooling path, and two dispersions in the slow heating path. Diisooctyl azelate and di-2-ethylhexyl sebacate showed one dispersion corresponding to glass transition in the slow cooling path, and two dispersions in the slow heating path. The rather peculiar behavior observed for the last pair is probably attributed to a wide separation between optimum temperatures for crystal growth and nucleation.