Glassy dynamics under superhigh pressure

Abstract

Nearly all glass-forming liquids feature, along with the structural alpha-relaxation process, a faster secondary process (beta relaxation), whose nature belongs to the great mysteries of glass physics. However, for some of these liquids, no well-pronounced secondary relaxation is observed. A prominent example is the archetypical glass-forming liquid glycerol. In the present work, by performing dielectric spectroscopy under superhigh pressures up to 6 GPa, we show that in glycerol a significant secondary relaxation peak appears in the dielectric loss at P>3 GPa. We identify this beta relaxation to be of Johari-Goldstein type and discuss its relation to the excess wing. We provide evidence for a smooth but significant increase in glass-transition temperature and fragility on increasing pressure.

Positron annihilation and broadband dielectric spectroscopy: A series of propylene glycols

“…a second power law at the high-frequency flank of the α-peak is observed. The latter can be ascribed to a submerged slow secondary relaxation [36][37][38]. On the other hand, the dimer and trimer are typical Type B glass-formers as at frequencies beyond the α-relaxation process a secondary relaxation peak shows up [39].…”

Spectroscopic features of ultrahigh-pressure impact glasses of the Kara astrobleme

“…Under laboratory conditions, at extremely high pressures, only small amounts of matter are produced, which are limited to particles of micrometer size at a pressure up to 100 GPa, where the synthesis is carried out preferably at room temperature 1–5 . Simultaneous combination of ultrahigh temperatures and pressures can theoretically be accompanied by the formation of specific materials 7 , which still requires a serious study.…”

New Challenges for the Pressure Evolution of the Glass Temperature

“…23. Experimental data are from author's measurements and from Cook et al (1994), Drozd-Rzoska (2005), Drozd-Rzoska et al (2007a), Pronin et al (2010). The dashed line and stars (in magenta) in the negative pressures domain denotes the possible absolute stability limit location: this was determined from the analysis of τ(P) experimental data via Eq.…”