Pressure and temperature dependence of structural relaxation dynamics in polymers: a thermodynamic interpretation

We analyse the slowing down of the structural relaxation dynamics of polymers in terms of the Adam and Gibbs theory. We consider a previously derived general relation between the configurational and the excess entropy, which was used to derive an analytical equation for the dependence of the structural relaxation time from the pressure and temperature. The model proved to successfully fit the relaxation dynamics of poly(methyl methacrylate), poly(propylene glycol) and poly(propylene glycol dimethylether), of different molecular weights, over a wide region of temperature and pressure values above the glass transition.