4. Effect of Glycine on Glass Transition Temperature of Sucrose Solution(Papers presented at the 39th Annual Meeting)

Abstract

The liquid-solid thermal equilibrium and the glass transition behaviour for glycine solution and sucrose-glycine mixture were investigated by using DSC. For glycine solutions the glass transition was not observed at all, but instead, it was found that a eutectic mixture of glycine and ice is formed during freezing. On reheating the eutectic mixtures, the crystal form of glycine changed from β type to α type. For sucros-eglycine blends, a typical glass transition was recognized on DSC heating curves, and the transition temperature decreased as the weight ratio of glycine increased. This shows that glycine effects on glassy sucrose as a plasticizer. These results, concerning the relation between the glass transition temperature and the weight fraction of glycine, could be represented by a semi-empirical equation. It was possible to figure a ternary state diagram by the combination of three binary state diagrams, sucrose-glycine, sucrose-water and glycine-water. Although the ternary state diagram is not complete, it could predict the behaviour during freezing of the ternary system.