The evaluation of the dynamic data near Tg from a new aspect

In this work, we compare and analyze the G$_{g}$ obtained by the KWW\footnote{G. Williams and D. C. Watts, Trans. Faraday Soc. 66, 80 (1970); F. Kolrausch, Pogg. Ann. Phys. 12, 393 (1847).} and the BSW\footnote{M. Baumg\"{a}rtel, A. Schausberger, and H. H. Winter, Rheol. Acta 29, 400 (1990).} functions for small molecule, polymer and colloidal glass formers in the context of the Dyre shoving model.\footnote{J. C. Dyre, N. B. Olsen, and T. Christensen, Phys. Rev. B 53, 2171 (1996).} The Dyre shoving model relates G$_{g}$ with temperature by attributing the free-energy barrier for a ``flow event'' near to T$_{g}$ to the work done by shoving aside the surrounding molecules; the free-energy barrier is proportional to G$_{g}$, which increases as the temperature decreases. Importantly, the model gives a non-singular growth of the relaxation time or viscosity with decreasing temperature and does not invoke ideas related to dynamic heterogeneity and growing length scales, both of which are commonly used in the description of glassy dynamics. To the extent that the material classes investigated seem to be reasonably described by the shoving model, it is suggested that divergence of time scales and length scales may not be essential to the glass transition phenomenon.