A Low-Temperature Amorphous Phase in a Fragile Glass-Forming Substance

1996 ◽  
Vol 100 (20) ◽  
pp. 8518-8526 ◽  
Author(s):  
Itai Cohen ◽  
Alice Ha ◽  
Xiaolin Zhao ◽  
Michelle Lee ◽  
Thomas Fischer ◽  
...  
Keyword(s):  
Low Temperature ◽  
Amorphous Phase ◽  
Glass Forming ◽  
Fragile Glass

The Application of X-Ray Diffraction at Elevated Temperatures to Study the Mechanism of Formation of Sodium Tripolyphosphate

1961 ◽  
Vol 5 ◽  
pp. 276-284
Author(s):  
E. L. Moore ◽  
J. S. Metcalf
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Amorphous Phase ◽  
Elevated Temperatures ◽  
Sodium Tripolyphosphate ◽  
X Ray Diffraction ◽  
Mechanism Of Formation ◽  
X Ray ◽  
Temperature Form ◽  
High Temperature Form

AbstractHigh-temperature X-ray diffraction techniques were employed to study the condensation reactions which occur when sodium orthophosphates are heated to 380°C. Crystalline Na4P2O7 and an amorphous phase were formed first from an equimolar mixture of Na2HPO4·NaH2PO4 and Na2HPO4 at temperatures above 150°C. Further heating resulted in the formation of Na5P3O10-I (high-temperature form) at the expense of the crystalline Na4P4O7 and amorphous phase. Crystalline Na5P3O10-II (low-temperature form) appears after Na5P3O10-I.Conditions which affect the yield of crystalline Na4P2O7 and amorphous phase as intermediates and their effect on the yield of Na5P3O10 are also presented.

Length scales for fragile glass‐forming liquids

1995 ◽  
Vol 102 (13) ◽  
pp. 5408-5410 ◽  
Author(s):  
Raymond D. Mountain
Keyword(s):  
Length Scales ◽  
Glass Forming ◽  
Fragile Glass

Dynamics in a Nonfragile Glass-Forming Liquid

1996 ◽  
Vol 455 ◽  
Author(s):  
B. Rufflé ◽  
S. Beaufils ◽  
J. Etrillard ◽  
J. Gallier ◽  
B. Toudic ◽  
...  
Keyword(s):  
Structural Relaxation ◽  
Mode Coupling ◽  
Low Frequency ◽  
Large Temperature ◽  
Coupling Theory ◽  
Mode Coupling Theory ◽  
Glass Forming ◽  
Real Change ◽  
Wide Energy ◽  
Fragile Glass

ABSTRACTThe dynamics of Na0.5Li0.5PO3 (Tg = 515 K, Tm = 749 K) a non fragile glass forming liquid has been investigated over a large temperature range (300 − 1000 K.) and in a wide energy window using various experimental techniques. The susceptibility spectra obtained by coherent neutron scattering and depolarized light scattering between 1 and 104 GHz show mainly two contributions: a low frequency vibrational peak, the so-called Boson peak and a quasielastic component, referred to the βfast process in the mode coupling theory (MCT).The data are discussed in relation to the mode coupling theory for the liquid glass transition. In particular, the temperature evolution of the susceptibility height in the βfast region is compatible with a crossover temperature Tc ∼ 620 K which is also deduced from a power law temperature dependence of the structural relaxation timescale. As a secondary βslow process, observed by 31P NMR, decouples from the structural relaxation timescale also below 600 K, a real change in the dynamics seems to occur around Tc ∼ 620 K = 1.2 Tg in this non fragile glass Conning liquid.

Light scattering measurement of shear viscosity in a fragile glass-forming liquid, metatoluidine

1998 ◽  
Vol 42 (1) ◽  
pp. 55-60 ◽  
Author(s):  
C Dreyfus ◽  
A Aouadi ◽  
R. M Pick ◽  
T Berger ◽  
A Patkowski ◽  
...  
Keyword(s):  
Light Scattering ◽  
Shear Viscosity ◽  
Glass Forming ◽  
Fragile Glass ◽  
Light Scattering Measurement ◽  
Scattering Measurement

Translation-rotation paradox for diffusion in fragile glass-forming liquids

1994 ◽  
Vol 50 (3) ◽  
pp. 2064-2068 ◽  
Author(s):  
Frank H. Stillinger ◽  
Jennifer A. Hodgdon
Keyword(s):  
Glass Forming ◽  
Fragile Glass

Time-resolved optical Kerr effect in a fragile glass-forming liquid, salol

1998 ◽  
Vol 57 (2) ◽  
pp. 1912-1920 ◽  
Author(s):  
Renato Torre ◽  
Paolo Bartolini ◽  
Robert Pick
Keyword(s):  
Kerr Effect ◽  
Optical Kerr Effect ◽  
Time Resolved ◽  
Glass Forming ◽  
Fragile Glass

scholarly journals Effects of the Glass-Forming Ability and Annealing Conditions on Cocrystallization Behaviors via Rapid Solvent Removal: A Case Study of Voriconazole

Pharmaceutics ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1209
Author(s):  
Si Nga Wong ◽  
Susan Wing Sze Chan ◽  
Xuexin Peng ◽  
Bianfei Xuan ◽  
Hok Wai Lee ◽  
...  
Keyword(s):  
Amorphous Phase ◽  
Binary Systems ◽  
Annealing Temperature ◽  
Glass Forming Ability ◽  
Dissolution Behavior ◽  
Solvent Removal ◽  
Glass Forming ◽  
Annealing Conditions ◽  
Avrami Kinetics ◽  
Cocrystal Screening

The kinetic entrapment of molecules in an amorphous phase is a common obstacle to cocrystal screening using rapid solvent removal, especially for drugs with a moderate or high glass-forming ability (GFA). The aim of this study was to elucidate the effects of the coformer’s GFA and annealing conditions on the nature of amorphous phase transformation to the cocrystal counterpart. Attempts were made to cocrystallize voriconazole (VRC) with four structural analogues, namely fumaric acid (FUM), tartaric acid (TAR), malic acid (MAL), and maleic acid (MAE). The overall GFA of VRC binary systems increased with decreasing glass transition temperatures (Tgs) of these diacids, which appeared as a critical parameter for predicting the cocrystallization propensity such that a high-Tg coformer is more desirable. A new 1:1 VRC-TAR cocrystal was successfully produced via a supercooled-mediated re-cocrystallization process, and characterized by PXRD, DSC, and FTIR. The cocrystal purity against the annealing temperature displayed a bell-shaped curve, with a threshold at 40 °C. The isothermal phase purity improved with annealing and adhered to the Kolmogorov–Johnson–Mehl–Avrami kinetics. The superior dissolution behavior of the VRC-TAR cocrystal could minimize VRC precipitation upon gastric emptying. This study offers a simple but useful guide for efficient cocrystal screening based on the Tg of structurally similar coformers, annealing temperature, and time.

Strong-fragile glass forming liquid concept applied to GeTe chalcogenide glasses

2001 ◽  
Vol 304 (1-4) ◽  
pp. 228-236 ◽  
Author(s):  
K. Chebli ◽  
J.M. Saiter ◽  
J. Grenet ◽  
A. Hamou ◽  
G. Saffarini
Keyword(s):  
Chalcogenide Glasses ◽  
Glass Forming ◽  
Fragile Glass
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