The Link Between the Pressure Evolution of the Glass Temperature in Colloidal and Molecular Glass Formers

Abstract

Recently, Voigtmann [Phys. Rev. Lett. 101, 095701 (2008)] suggested the existence of the universal “generic steep“ behavior for the glass pressure vs. temperature dependence in molecular glass formers. We indicate that such behavior disappear when the absolute stability limit in the negative pressures domain is taken as the reference. It is a parasitic artifact of omitting the stability limit in the negative pressures domain for the log-log scale plot. Results presented suggest a totally common pattern for the evolution of the glass temperature in colloidal fluids and molecular liquids. However, for molecular liquids both positive and negatives pressures domains have to be taken into account. Consequently the pattern for colloidal glass formers introduced by Sciortino “One Liquid, Two Glasses“ [Nature Materials 1, 1-3 (2002)] may appear to be valid also for molecular glass formers.