Correspondence Between the Configurational Enthalpy Model and the Relaxation Dynamics of Simulated Amorphous Polymers above Tg

Glass forming materials exhibit dramatic mobility decreases of up to ten orders of magnitude as their temperature approaches Tg. This slow-down exhibits a super-Arrhenian temperature dependence that is diagnostic for testing competing theories of glass formation. Using experimental data, it was recently shown that for 21 molecular glass formers a simple one-parameter model based on the excess enthalpy accurately predicts the super-Arrhenian behavior, whereas the traditional configurational entropy model of Adam-Gibbs shows significant deviations. Extending this analysis to polymeric materials is challenging since the requisite experimental data is limited. Here we present simulations on several common small molecules and polymers to explore the temperature dependence of the polymer dynamics in the supercooled regime, making comparisons with the new configurational enthalpy model and experimental data where available. We show that the configurational enthalpy model accurately describes the temperature and pressure dependence of the mobility slowdown in the studied polymers. Moving forward this provides justification for using simulations to investigate the molecular mechanisms responsible for the accurate predictions of the configurational enthalpy model.