Relation between the activation energy of the Johari-Goldstein β relaxation and Tg of glass formers -: art. no. 031501

For glass-forming substances, we show that the ratio E-beta/RTg can be predicted quantitatively from the coupling model. Here E-beta is the glassy state activation enthalpy of the Johari-Goldstein beta relaxation, T-g is the glass transition temperature of the alpha relaxation, and R is the gas constant. The calculated value is in good agreement with the experimental value in many glass formers. The results locate the origin of this cross correlation between E-beta of the Johari-Goldstein beta relaxation and T-g of the alpha relaxation, although there are some notable exceptions to this cross correlation.