Freezing behaviour of dextran aqueous solutions was investigated by differential scanning calorimetry (DSC). It was found, as a result, that the DSC heating traces obtained with the frozen solutions indicate a small endotherm before the appearance of a large endotherm due to ice melting at ca. 0℃. The small endotherm shifted toward a higher direction by several degrees after the equilibrium freezing, when compared with the nonequilibrium freezing after the substantial undercooling. Origin of the small endotherm was considered to be melting of small ice crystals confined within the intramolecular space of entangled dextrans which melt at lower temperatures due to Kelvin effect.
