title: Specific heat relaxation of an alcohol and implications for dielectric comparison.
abstract: The dynamic and the apparent specific heats of 5-methyl-2-hexanol were measured in its vitrification temperature range during its cooling and then heating at the same and exceptionally slow rates of 12 K/h and 60 K/h. The relaxation time determined from dynamic measurements is 48 s at 149.8 K. The relaxation time estimated from the onset of the apparent C(p)-endotherm measured on heating is found to be inconsistent with that determined from dynamic C(p) measurements. The fitting of a nonexponential nonlinear relaxation model to the C(p,app) data shows that beta varies slightly with the heating rate, and this is attributed to contributions to temperature-dependent energy from change in the hydrogen-bond population. The unrelaxed C(p) of the ultraviscous liquid is closer to that of its glassy state, thus showing that the vibrational part of C(p) does not increase in a sigmoid-shape manner when the glass structure kinetically unfreezes on heating. The results have implications for use of calorimetry in inferring the dielectric relaxation mechanism.
authors.affiliation: Istituto per i Processi Chimico-Fisici, CNR, Via G. Moruzzi 1, 56124 Pisa, Italy. tombari@ipcf.cnr.it
authors.forename: E
authors.initials: E
authors.lastname: Tombari
authors.forename: C
authors.initials: C
authors.lastname: Ferrari
authors.forename: G
authors.initials: G
authors.lastname: Salvetti
authors.forename: G P
authors.initials: GP
authors.lastname: Johari