PRESSURE-VOLUME TEMPERATURE RELATIONS AND CONFIGURATIONAL ENERGY OF LIQUID, CRYSTAL, AND GLASSES OF D-SORBITOL

Pressure-volume-temperature relations of the liquid, the supercooled l iquid, the crystal, and two glasses of D-sorbitol are presented, and c haracteristics of the glass transition and the melting are reported. T he glasses were vitrified from the liquid by isobaric cooling at a rat e of -0.2 K/min under 0.1 and 78.5 MPa. Vitrification pressure alters effectively the properties of the glasses. The thermal expansivity and the internal pressure of the higher-density glass vitrified under 78. 5 MPa are higher than those of the lower-density glass vitrified under the atmospheric pressure. With the aid of the result of the dielectri c activation process in the liquid, these properties are interpreted b y the number of frozen-in high-energy and high-density regions which h ave presumably been produced from defects and weak portions of the int ermolecular hydrogen-bonding networks in the liquid at the vitrificati on points. A simple configurational energy consisting of a Lennard-Jon es contribution and a hydrogen-bond contribution is proposed and has b een applied to the glasses and the crystal.