3. THE GLASS STATE AND THE GLASS TRANSITION: THERMODYNAMIC and KINETIC ASPECTS

Differential Scanning Calorimetry Differential Thermal Analysis

Is the glass transition a true thermodynamic phase transition ?  T g depends on the cooling rate  T g depends on the thermal history

sub-T g aging and annealing T anneal.

Phase transitions of 1st and 2nd order (Ehrenfest classification) Clausius-Clapeyron Ehrenfest

Phase transitions of 1st and 2nd order (Ehrenfest classification)

1st-order, 2nd-order and Lambda-type transitions v 1  v 2 s 1  s 2 c p, ,  T   v 1 = v 2 s 1 = s 2 c p, ,  T   v 1 = v 2 s 1 = s 2 c p1  c p2  1   2  T1   T2 [ T 1 = T 2 ; P 1 = P 2 ; g 1 = g 2 ]

Ehrenfest relations Prigogine-Defay ratio must be = 1 if it were a phase transition with a single order parameter

using Differential Scanning Calorimetry (DSC, TMDSC…) [J. M. Hutchinson, Thermochimica Acta 324 (1998)

using Differential Scanning Calorimetry

the fictive temperature T f B2O3B2O3 [M. A. R. et al., J. Non-Cryst. Solids 221 (1997) 170]

the fictive temperature T f Ethanol [B. Kabtoul and M. A. R., Phys. Status Solidi A 208, 2249–2253 (2011)]

the fictive temperature T f  phenomenological Tool-Narayanaswamy-Moynihan (TNM) approach [ Tool, J. Am. Ceram. Soc. 29 (1946) 240. Narayanaswamy, J. Am. Ceram. Soc. 54 (1971) 491. Moynihan et al., J. Am. Ceram. Soc. 59 (1976) 12. ]  curve fitting method: [I. M. Hodge, J. Non-Cryst. Solids 169 (1994) 211]

THE KAUZMANN PARADOX EXCESS OF ENTROPY: TKTK

W. Kauzmann, Chem. Rev. 43, 219 (1948)

THE KAUZMANN PARADOXNN 1.0

STRONG AND FRAGILE GLASS-FORMING LIQUIDS 01

Vogel-Tamman-Fulcher equation: (D: strength) fragility index m:

STRONG AND FRAGILE GLASS-FORMING LIQUIDS C. A. Angell, J. Non-Cryst. Solids 102, 205 (1988)

[I. Chang and H. Sillescu] Stokes-Einstein equation: [A. Einstein, Annalen der Physik 17, 549 (1905)]

B2O3B2O3 o-terphenyl v   HH