Aging and Solidification of Supercooled Glycerol

Abstract

We experimentally investigate the solidification of supercooled glycerol during aging that has recently been observed by Zondervan et al. We find that a slow cooling at 5 K/h prior to the aging is required for solidification to take place. Furthermore, we show that the time of onset depends strongly on the aging temperature which we varied between 220 and 240 K. The nature of the solid phase remains unclear. The experiments show that upon heating the solid glycerol melts at the crystal melting point. However, rheology experiments in the plate-plate geometry revealed the growth of a soft, slushlike phase that is distinct from a crystal grown by seeding at the same aging temperature. The slushlike glycerol grows from a nucleation point at almost the same speed as a seeded crystal quenched to the same temperature, but its shear modulus is almost 2 orders of magnitude lower than the crystal phase, which we measure independently. While solidification was reproducible in the Couette geometry, it was not in the plate-plate geometry.

Communication: Crystallite nucleation in supercooled glycerol near the glass transition

“…3(a). This inhomogeneous solidification at the early stage is in good agreement with the observation by Möbius et al 14 On deuterated sample S 4 , as shown in Fig. 3(b), Bragg peaks started to appear and grow after 22 h at 220 K. Until the beam time was over, five peaks appeared on the diffraction pattern.…”

“…glycerol. 9,[12][13][14] We have evidence that a nucleation process takes place during aging at a temperature near T g . Nonetheless, crystallization strongly depends on the thermal history that the sample was submitted to.…”

“…Hence, the structural origin of the solid-like structure developed in supercooled glycerol near T g becomes significantly important for a better understanding on previous experimental observations. 9,[12][13][14] To get more insight into the structural organization of the solid-like network and on the solid-like fraction of the sample, we performed neutron diffraction and inelastic neutron scattering.…”

Liquid dynamics in partially crystalline glycerol

“…The fact that in one of the samples studied here (Fig. 5) the end of the crystallization was suddenly aborted could explain prior results that speculated the formation of a glacial phase in which metastable nano-crystals were embedded in a liquid matrix 18,24,25 . Our data just show an unfinished ordering process that resulted in a small fraction of sample remaining in the liquid state.…”

Physicochemical and Structural Properties of Glycerin Gel Prepared using Glycyrrhizic Acid Diethyl Ester

“…This shows that JP glycerin and glycerin gel remained a liquid state without even freezing point or less becoming the solid by not having regular arrangement of glycerin molecules for this temperature change 10 /min . In addition, it was reported that the condition to crystallize glycerin at freezing point temperature was to heat glycerin at the speed of 1 /min after cooling to 80 at the speed of 5 /min 15 . If there is little interaction between GZ-DE and glycerin, the DSC curve of glycerin gel will be similar to that of a simple physical mixture of GZ-DE and glycerin.…”