Figure 2. Isobaric specific heat and density for glasses of the SPC/E model on heating.

(a) Isobaric specific heat, c_P(T), and (b) density, ρ(T), upon heating compressed HGW (solid lines) and decompressed HDA (dashed lines) at various pressures. T_g(P) (defined by the inflection of c_P(T) below its maximum temperature) occurs at nearly the same temperature for compressed HGW and decompressed HDA. However, the behavior of the c_P(T) and ρ(T) differ significantly in the glassy state (e.g., at T < 200 K for all pressures). For clarity, curves in (a) have been successively shifted by 30 kJ/(K·mol) for increasing pressure.