2
0
2017
rig
tom
0
journal
Original
Righetti, M. C.[Maria Cristina]
Tombari, E.[Elpidio]
Johari, G. P.
Thermochim. Acta
2017
2020-09-29
Endothermic features on heating of glasses show that the second glass to liquid transition of water was phenomenologically-mistaken
When glasses formed by cooling at different rates are heated at the same rate, they show different shapes of the glass to liquid transition endotherm in their Cp-T plot and different onset temperatures of the Cp-endotherm. (This temperature is taken as the glass to liquid transition temperature. To prevent confusion we denote it as Tg l.) According to the phenomenology of glass to liquid transition, (i) a glass formed by slower cooling shows on heating a higher Tg lthan a glass formed by rapid cooling and (ii) the Cp-endotherm fs shape changes and its enthalpy recovery overshoot becomes higher. But a recent study arbitrarily asserted the opposite, namely, that a glass formed by slower cooling of a liquid has a lower Tg l, and this feature is "a typical signature of a glass transition". By using that gsignature h the study concluded that an ill-defined state of solid water has a gsecond Tg h (Tg lin the terminology here) at 116 K. The assertion caused us to perform a calorimetric study of the glass to liquid transition phenomenon in eight materials by using the same cooling/heating protocols that had led to the assertion of the signature. Our study confirms the already known glass phenomenology. Therefore, ga typical signature for aglass transition h is false, and the second Tg(or Tg l) at 116 K based on the study of an ill-defined solidwater (formed by annealing the pressure-collapsed state of ice) was phenomenologically-mistaken. Ina different context, we quantify the dependence of Tg lon the cooling rate and compare the effect of slow cooling against the effects of annealing (ageing) on the properties of the glassy state. The study hasadverse consequences for some models of the structure of water.
Glass transition
Water
Polymer
Glass phenomenology
10.1016/j.tca.2016.11.011
647
101-110
1
InChI=1S/C8H9NO2/c1-6(10)9-7-2-4-8(11)5-3-7/h2-5,11H,1H3,(H,9,10)
RZVAJINKPMORJF-UHFFFAOYSA-N
N-acetyl-p-aminophenol
4'-hydroxyacetanilide
4-acetamidophenol
4-hydroxyacetanilide
N-(4-hydroxyphenyl)acetamide
N-(4-hydroxyphenyl)ethanamide
acetagesic
acetamide, N-(4-hydroxyphenyl)-
acetaminophen
acetanilide, 4'-hydroxy-
p-acetamidophenol
p-hydroxyacetanilide
panadol
paracetamol
tempra
C8H9NO2
1
Commercial source
1
99
2
Stated by supplier
2
InChI=1S/C17H18N2O6/c1-9-13(16(20)24-3)15(14(10(2)18-9)17(21)25-4)11-7-5-6-8-12(11)19(22)23/h5-8,15,18H,1-4H3
HYIMSNHJOBLJNT-UHFFFAOYSA-N
dimethyl 4-(2-nitrophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate
Nifedipine
C17H18N2O6
1
Commercial source
1
99
2
Stated by supplier
3
InChI=1S/C6H10O5/c7-3-2-1-10-6(11-2)5(9)4(3)8/h2-9H,1H2/t2-,3-,4+,5-,6-/m1/s1
TWNIBLMWSKIRAT-VFUOTHLCSA-N
1,6-anhydro-.beta.-D-glucopyranose
1,6-dihydro-.beta.-D-glucopyranose
levoglucosan
C6H10O5
1
Commercial source
1
99
2
Stated by supplier
1
1
1
Principal objective of the work
AB
TRC
3/7/2017
1
Triple point temperature, K
DSC
Glass
Direct value, X
1
Data file compiler
Propagation of evaluated standard uncertainties
95
Glass
Liquid
Air at 1 atmosphere
1
297
4
1
1
2
1
1
Principal objective of the work
AB
TRC
3/7/2017
1
Triple point temperature, K
DSC
Glass
Direct value, X
1
Data file compiler
Propagation of evaluated standard uncertainties
95
Glass
Liquid
Air at 1 atmosphere
1
294.8
4
1
1
3
2
1
Principal objective of the work
AB
TRC
3/7/2017
1
Triple point temperature, K
DSC
Glass
Direct value, X
1
Data file compiler
Propagation of evaluated standard uncertainties
95
Glass
Liquid
Air at 1 atmosphere
1
317.6
4
1
1
4
2
1
Principal objective of the work
AB
TRC
3/7/2017
1
Triple point temperature, K
DSC
Glass
Direct value, X
1
Data file compiler
Propagation of evaluated standard uncertainties
95
Glass
Liquid
Air at 1 atmosphere
1
315.4
4
1
1
5
3
1
Principal objective of the work
AB
TRC
3/7/2017
1
Triple point temperature, K
DSC
Glass
Direct value, X
1
Data file compiler
Propagation of evaluated standard uncertainties
95
Glass
Liquid
Air at 1 atmosphere
1
248.4
4
1
1
6
3
1
Principal objective of the work
AB
TRC
3/7/2017
1
Triple point temperature, K
DSC
Glass
Direct value, X
1
Data file compiler
Propagation of evaluated standard uncertainties
95
Glass
Liquid
Air at 1 atmosphere
1
246.6
4
1
1