Studies on Glass. XI. Some Thermodynamic Relations of Glassy and Alpha-Crystalline Glucose

Abstract

Although the properties of a glass depend to some extent upon its thermal history, the view is expressed that fairly satisfactory thermodynamic data can be obtained for well‐annealed glasses. In the present study the difference between the heat contents of glucose glass and α‐crystals has been determined calorimetrically at 20°C and with the aid of this result the corresponding differences in entropy and free energy have also been computed. The value for this last quantity is ΔF°₂₉₃ = 1670 cal. per mol. Solubility measurements have been made for glucose α‐crystals and glass in methyl, ethyl and isopropyl alcohols at 20°. The free energy values thereby obtained for the conversion of α‐crystals into glassy glucose are in good agreement with the preceding value derived from the thermal data.