Molecular mobility studies on the amorphous state of disaccharides. I-thermally stimulated currents and differential scanning calorimetry.
The relaxational processes in amorphous solid gentiobiose and cellobiose are studied by thermally stimulated depolarization currents (TSDC) in the temperature region from 108K up to 423K. The slow molecular mobility was characterized in the crystal and in the glassy state. The features of different motional components of the secondary relaxation have been monitored as a function of time as the glass structurally relaxes on aging. It is concluded that some modes of motion of this mobility are aging independent, while others are affected by aging. The value of the steepness index or fragility (T(g)-normalized temperature dependence of the relaxation time) was obtained by differential scanning calorimetry (DSC) from the analysis of the scanning rate dependency of T(g).
Pinto
Susana S
SS
Centro de Química Estrutural, Complexo I, IST, TULisbon, Av. Rovisco Pais 1049-001 Lisboa, Portugal.
Diogo
Hermínio P
HP
Nunes
Teresa G
TG
Moura Ramos
Joaquim J
JJ
D002152:Calorimetry, Differential Scanning; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002475:Cellobiose / Q000737:chemistry*; D004187:Disaccharides / Q000737:chemistry*; D013696:Temperature
D004187:Disaccharides; D002475:Cellobiose; C100052:gentiobiose