Glass formation and glass transition in supercooled liquids, with insights from study of related phenomena in crystals

Abstract

Abstract.We divide glass and viscous liquid sciences into two major research areas, the first dealing with how to avoid crystals and so access the viscous liquid state, and the second dealing with how liquids behave when no crystals form. We review some current efforts to elucidate each area, looking at strategies for vitrification of monatomic metals in the first, and the origin of the property "fragility" in the second. Essential here is the nontrivial behavior of the glassformer thermodynamics. We explore the findings on nonexponential relaxation and dynamic heterogeneities in viscous liquids, emphasizing the way in which direct excitation of the configurational modes has helped differentiate configurational from nonconfigurational contributions to the excess heat capacity. We then propose a scheme for understanding the relation between inorganic network and non-network glassformers which includes the anomalous case of water as an intermediate. In a final section we examine the additional insights to be gained by study of the ergodicity-breaking, glass-like, transitions that occur in disordering crystals. Here we highlight systems in which the background thermodynamics is understood because the ergodic behavior is a lambda transition. Water and the classical network glassformers appear to be attenuated versions of these.

Rattling the cage: Micro- to mesoscopic structure in liquids as simple as argon and as complicated as water

“…[9,38,89,90] As the glass transition is approached, viscosity diverges away from simple Arrhenius behavior but may be described using the Vogel-Fulcher-Tammann (VFT) equation…”

“…[1,2] Changes in the degree and type of local structuring in water [3,4] may give rise to phenomena ranging from multiple crystalline phases to glass formation, and possible liquid-liquid phase transitions. [5][6][7][8][9][10][11] Recent studies on room temperature ionic liquids (RTILs [12,13]) have shown mesoscopic structure that is not liquid crystalline in origin. [14][15][16][17] Such RTILs may well form the micelle-like structure that is normally associated with amphiphilic properties.…”

Coupling of dielectric and mechanical relaxations with glass transition and stickiness of milk solids

“…The temperature dependence of the a-relaxation time (s a ) was modeled using the Vogel-Tamman-Fulcher (VTF) relationship of Eq. (1) (Chan et al, 1986;Angell et al, 1982;El Moznine et al, 2003;Angell, 2008).…”

“…As a glass-forming liquid is supercooled, its relaxation times and viscosity increase dramatically towards the glass transition (Angell et al, 1982). The temperature dependence of viscosity and relaxation times of amorphous materials above the glass transition can be described using the Vogel-Tammann-Fulcher (VTF) relationship (Angell, 1995(Angell, , 2002(Angell, , 2008Borde et al, 2002). Our previous studies (Silalai and Roos, 2010a,b) found a relationship between temperature dependence of a-relaxations and flow characteristics of milk powders above the T g and consequent dramatic changes in a-relaxations and stickiness occurred around the glass transition as a result of the increased molecular mobility and liquid bridging between particles (Silalai and Roos, 2010a,b).…”

Empirical and theoretical models of equilibrium and non-equilibrium transition temperatures of supplemented phase diagrams in aqueous systems (IUPAC Technical Report)

“…view of the glassy state (the "ideal glass-former" [161]) would emerge, as the understanding of crystallization kinetics would become irrelevant to the problem of understanding the existence of the glass transition. This could be regarded as an important research avenue.…”