Glass phase and other multiple liquid-to-liquid transitions resulting from two-liquid phase competition

Abstract

Melt supercooling leads to glass formation. Liquid-to-liquid phase transitions are observed depending on thermal paths. Viscosity, density and surface tension thermal dependences measured at heating and subsequent cooling show hysteresis below a branching temperature and result from the competition of two-liquid phases separated by an enthalpy difference depending on temperature. The nucleation classical equation of these phases is completed by this enthalpy saving existing at all temperatures. The glass phase thermodynamic parameters and their thermal variation have already been determined in such a two-liquid model. They are used at high temperatures to predict liquid-to-liquid transitions in some metallic glass-forming melts.

Dewetting temperatures of prefrozen and grafted layers in solid ultrathin films viewed as melt-memory effects

“…Ultrathin films (h < h0) are submitted to a decrease Tg of the glass transition temperature depending on h = (h-h0). The reduced temperature n+ is equal to (-0.38742×g) [28] (equation 28) and Tn+ does not vary with h as shown in chapter 3. The variation Tg is due to change of Tm .…”

“…The enthalpy coefficients are calculated with g2 = -0.16513 (Tg2 = 457.5 K) using (4)(5)(6)(7)(8)(9)26) to obtain lg = -0.15374 at Ta. They are given by (27)(28)(29):…”

Homogeneous nucleation of phase transformations in supercooled water

“…(7,8). There is a transition from Liquid 1 to Liquid 2 at TBr+ and TBr-, the temperatures where ls becomes equal to gs below and above Tm [41]. This crossover has been observed on Vit 1 in 2007, studying the liquid viscosity above Tm and around TBr+ [79].…”

Undercooled phase behind the glass phase with superheated medium-range order above glass transition temperature

“…The amorphous state obtained after hyper-quenching does not respect the Kauzmann's entropy constraint [18][19][20][21][22][23][24]. Superclusters and the glass phase are built by reheating the amorphous liquid from a nucleation temperature Tn-far below Tg and up to a second homogeneous nucleation temperature Tn-= Tg with formation of a new phase called Phase 3 respecting the Kauzmann constraints [13,16].…”

“…Superclusters and the glass phase are built by reheating the amorphous liquid from a nucleation temperature Tn-far below Tg and up to a second homogeneous nucleation temperature Tn-= Tg with formation of a new phase called Phase 3 respecting the Kauzmann constraints [13,16]. The thermodynamic parameters of this new supercooled phase are obtained in a model involving two liquid states separated by their Gibbs free energy difference determined from the value of Tg [23,25,26]. This model has some analogy with the concept of two liquids applied to supercooled water transformations [27].…”