Calculated and observed change of configuration heat capacity. Comparison of calculated and observed change of configuration heat capacity, C
, across the glass transition for a hydrous phonolite melt as a function of water content of the melt. Experimental data for phonolite from Bouhifd et al. (2006). Structural and thermodynamic data used to derive partial molar configurational entropy of Qn species are from Mysen (2010a) and Richet and Neuville (1992), respectively. This calculation was originally reported in Mysen (2007).