Binary glass-forming materials: Mixtures of sorbitol and glycerol

The dynamics of sorbitol/glycerol mixtures across the entire composition range has been characterized by dielectric relaxation measurements for frequencies between 10 mHz and 10 MHz. We explore the gradual change in the glass transition temperature (T-g), fragility (m), nonexponentiality (beta(KWW)), and occurrence of a secondary Johari-Goldstein type relaxation as a function of the mole fraction. Regarding the crystallization tendency at room temperature and the freezing of molecular motion below Tg, these mixtures differ qualitatively from aqueous solutions of sugars or other polyols.