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

Cohen, Itai; Ha, Alice; Zhao, Xiaolin; Lee, Michelle; Fischer, Thomas M.; Strouse, M. Jane; Kivelson, Daniel

doi:10.1021/jp953785h

Cited by 147 publications

(190 citation statements)

References 44 publications

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“…The subtle intensity changes that do occur are typical of data on many supercooled organic liquids (36). This is in contrast to literature reports for liquid TPP (40). For TPP, a liquid-toliquid phase transition has been reported a few degrees Kelvin above T g ; the stable state at low temperature (the ''glacial'' state) has a significantly different WAXS pattern than that of the supercooled liquid obtained at slightly higher temperatures.…”

Section: Resultscontrasting

confidence: 75%

“…As mentioned above, a first-order liquid-to-liquid transition has been reported for TPP slightly above T g at atmospheric pressure (40)(41)(42). A first-order transition between two liquid states with the same composition has also been reported for 20-32 mol % Y 2 O 3 in Y 2 O 3 -Al 2 O 3 melts at Ϸ1500 K (49,50).…”

Section: Indications Of a First-order Phase Transition Experiments Lsupporting

confidence: 55%

“…A first-order transition has been reported to occur in TPP at ambient pressure a few degrees Kelvin above T g (40)(41)(42). To our knowledge, a liquid-to-liquid transition occurring below the conventional T g has not been previously shown.…”

mentioning

confidence: 73%

“…This result could be understood as indicating either that our aging temperature was not low enough or that the transformation time to the LT glass form is very long. For TPP, annealing times longer than 10 5 ␣ were required to transform the higher-temperature liquid into the lower-temperature liquid (as known as the glacial state) (40,59). For IMC at room temperature, 10 5 ␣ is Ϸ10 5 y.…”

Section: Indications Of a First-order Phase Transition Experiments Lmentioning

confidence: 99%

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Physical vapor deposition as a route to hidden amorphous states

Dawson

Kearns

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

106

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Stable glasses of indomethacin (IMC) were prepared by using physical vapor deposition. Wide-angle X-ray scattering measurements were performed to characterize the average local structure. IMC glasses prepared at a substrate temperature of 0.84 Tg (where Tg is the glass transition temperature) and a deposition rate of 0.2 nm/s show a broad, high-intensity peak at low q values that is not present in the supercooled liquid or melt-quenched glasses. When annealed slightly above Tg, the new WAXS pattern transforms into the melt-quenched glass pattern, but only after very long annealing times. For a series of samples prepared at the lowest deposition rate, the new local packing arrangement is present only for deposition temperatures below Tg ؊20 K, suggesting an underlying first-order liquid-to-liquid phase transition.entropy ͉ glass ͉ liquid-liquid transition ͉ supercooled ͉ X-ray scattering I f a liquid is cooled to just below its melting point, one of two outcomes will be observed. If the liquid readily forms crystal nuclei, then crystals will form and grow. Otherwise, the system will remain in the now metastable liquid state. In the absence of crystallization, further cooling of this supercooled liquid will result in slower dynamics, and eventually, the dynamics will become so slow that the supercooled liquid cannot maintain its equilibrium state (1). At this glass transition temperature (T g ), the system properties deviate from the properties of the supercooled liquid, and a glass is formed.Whereas the liquid-to-crystal transition is a first-order phase transition, the supercooled liquid-to-glass transition is a kinetic event based on relaxation times growing rapidly as the temperature is decreased. A great deal of recent work has been concentrated on understanding the nature of slow dynamics in supercooled liquids (2-11). As a liquid is cooled at lower rates, more time is given for the system to find equilibrium, and thus, T g decreases. For many organic liquids, T g decreases 3-4 K for every order-of-magnitude decrease in the cooling rate. Because there is a practical limit as to how slowly a sample can be cooled, a glass always forms upon cooling (if crystallization does not occur).What if one could cool a supercooled liquid extremely slowly such that equilibrium was always maintained? There are good reasons to believe that something interesting must occur. In 1948, Kauzmann discussed the consequences of very slow cooling for the entropy of a supercooled liquid, which identified the so-called Kauzmann entropy crisis (12). For some liquids, if the entropy is extrapolated to low temperature, it becomes equal to that of the crystal not too far below the conventional T g ; further extrapolation leads to a negative entropy above absolute zero in violation of the third law of thermodynamics. Because this is impossible, it is generally assumed that the extrapolation that produces this crisis must be incorrect, and thus something interesting must occur when a supercooled liquid is cooled very slowly. Several theories...

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Section: Resultscontrasting

confidence: 75%

Section: Indications Of a First-order Phase Transition Experiments Lsupporting

confidence: 55%

mentioning

confidence: 73%

Section: Indications Of a First-order Phase Transition Experiments Lmentioning

confidence: 99%

See 2 more Smart Citations

Physical vapor deposition as a route to hidden amorphous states

Dawson

Kearns

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

106

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“…[10][11][12][13] There are some striking similarities between the slushy state of supercooled glycerol and the glacial state of TPP. For example, the rheological experiments on the glacial state of TPP shows that the maximum G′ is order of 10 6 Pa, 12 close to 10 7 Pa of the slushy phase of glycerol.…”

Section: Discussionmentioning

confidence: 99%

Aging and Solidification of Supercooled Glycerol

et al. 2010

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We experimentally investigate the solidification of supercooled glycerol during aging that has recently been observed by Zondervan et al. We find that a slow cooling at 5 K/h prior to the aging is required for solidification to take place. Furthermore, we show that the time of onset depends strongly on the aging temperature which we varied between 220 and 240 K. The nature of the solid phase remains unclear. The experiments show that upon heating the solid glycerol melts at the crystal melting point. However, rheology experiments in the plate-plate geometry revealed the growth of a soft, slushlike phase that is distinct from a crystal grown by seeding at the same aging temperature. The slushlike glycerol grows from a nucleation point at almost the same speed as a seeded crystal quenched to the same temperature, but its shear modulus is almost 2 orders of magnitude lower than the crystal phase, which we measure independently. While solidification was reproducible in the Couette geometry, it was not in the plate-plate geometry.

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Cooperative Bond Ordering in Liquid: Its Link to Liquid Polymorphism and Water‐Like Anomalies

Tanaka

2013

Liquid Polymorphism

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

Cited by 147 publications

References 44 publications

Physical vapor deposition as a route to hidden amorphous states

Physical vapor deposition as a route to hidden amorphous states

Aging and Solidification of Supercooled Glycerol

Cooperative Bond Ordering in Liquid: Its Link to Liquid Polymorphism and Water‐Like Anomalies

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