Abstract
To obtain the basically knowledge of the molecular mobility of low molecular carbohydrate under the glassy state, the enthalpy relaxation time (τ) of five sugars such as glucose, galactose, maltose, sucrose and trehalose, were examined through aging experiment by using DSC. The glassy samples were aged at several temperatures of (T_g-10) K to (T_g-35) K. The r at each temperature was obtained by fitting Kohlrausch-Williams-Watts (KWW) equation to the time course of enthalpy relaxation amount (ΔH). When the temperature dependence of molecular mobility was assumed as Arrhenius process, the activation energy amount (ΔE) could be estimated. Judging from the ΔE value, it can be considered that the enthalpy relaxation is mainly due to α-relaxation process governing the molecular dynamics. Furthermore, the ΔE was larger in order of trehalose>galactose>sucrose>maltose>glucose. The result would support the explanation of availability of glassy trehalose as lyoprotectant of protein or biosystem under the severe circumstance.
