Calorimetric study of l,d-propene carbonate: observation of the β- as well as α-glass transition in the supercooled liquid

Abstract

Heat capacities of l,d-propene carbonate c -CH2·O·CO·O·CH(CH3) were measured with an adiabatic calorimeter in the temperature range 13 < (T/K) < 300 and the standard thermodynamic functions were evaluated. The triple-point temperature and molar enthalpy and molar entropy of fusion were determined to be (218.66 ± 0.02) K, (8.011 ± 0.008) kJ·mol-1, and (36.64 ± 0.04) J·K-1·mol-1, respectively. The heat-capacity jump associated with the α-glass transition at T = (156 ± 1) K was found to be (71.9 ± 0.4) J·K-1·mol-1. A β-glass transition was discovered for the first time in the glassy state at T = (64 ± 2) K with a heat-capacity jump of (0.04+0.04-0.02) J·K-1·mol-1. Moreover, heat evolution accompanied by sound and a flash of visible light was observed during d.t.a. when the sample vitrified.