A Raman study of B203 through the liquid-glass transition range

The low frequency Raman spectrum of B203 and the boroxol ring vibrational mode at 808 cm-1 have been studied from room temperature to 1273 K as the glass transforms to a melt. Both the low frequeney "boson" peak and the boroxol mode are markedly influenced by the glass transition. Raising the temperature above Tg the strength of the 808 cm-1 mode decreases linearly indicating the Similar behavior of the boroxol ring concentration. The boson peak shows a different temperature behavior, which mirrors that of the sound velo city. The structural correlation length demostrates the same correlation range in the liquid and the glass. The results, when compared with neutron diffraction measurements contradict a recently proposed relation between the "boson correlation length" and the position of the first sharp diffraction peak of the structure factor.

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Low frequency Raman study of the Boson peak in a Tellurite-tungstate glass over temperature

Journal of Non-Crystalline Solids ◽

10.1016/j.jnoncrysol.2017.11.002 ◽

2018 ◽

Vol 481 ◽

pp. 295-298

Author(s):

M.P. Belançon ◽

G. Simon

Keyword(s):

Low Frequency ◽

Boson Peak ◽

Raman Study

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A low-frequency Raman study of glassy, supercooled and molten silica and the preservation of the Boson peak in the equilibrium liquid state

Journal of Non-Crystalline Solids ◽

10.1016/j.jnoncrysol.2006.02.163 ◽

2006 ◽

Vol 352 (42-49) ◽

pp. 4619-4624 ◽

Cited By ~ 35

Author(s):

A.G. Kalampounias ◽

S.N. Yannopoulos ◽

G.N. Papatheodorou

Keyword(s):

Liquid State ◽

Low Frequency ◽

Boson Peak ◽

Raman Study

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Boson peak, elasticity, and glass transition temperature in polymer glasses: Effects of the rigidity of chain bending

Scientific Reports ◽

10.1038/s41598-019-55564-2 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 7

Author(s):

Naoya Tomoshige ◽

Hideyuki Mizuno ◽

Tatsuya Mori ◽

Kang Kim ◽

Nobuyuki Matubayasi

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Low Frequency ◽

Peak Frequency ◽

Boson Peak ◽

Polymer Chains ◽

Coarse Grained ◽

Elastic Response ◽

Bending Rigidity

AbstractThe excess low-frequency vibrational spectrum, called boson peak, and non-affine elastic response are the most important particularities of glasses. Herein, the vibrational and mechanical properties of polymeric glasses are examined by using coarse-grained molecular dynamics simulations, with particular attention to the effects of the bending rigidity of the polymer chains. As the rigidity increases, the system undergoes a glass transition at a higher temperature (under a constant pressure), which decreases the density of the glass phase. The elastic moduli, which are controlled by the decrease of the density and the increase of the rigidity, show a non-monotonic dependence on the rigidity of the polymer chain that arises from the non-affine component. Moreover, a clear boson peak is observed in the vibrational density of states, which depends on the macroscopic shear modulus G. In particular, the boson peak frequency ωBP is proportional to $$\sqrt{G}$$G. These results provide a positive correlation between the boson peak, shear elasticity, and the glass transition temperature.

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Low-frequency vibrational mode anomalies and glass transition: Thermal stability, phonon scattering, and pressure effects

Physical Review B ◽

10.1103/physrevb.78.094203 ◽

2008 ◽

Vol 78 (9) ◽

Cited By ~ 12

Author(s):

Gerardo G. Naumis ◽

Hugo M. Flores-Ruiz

Keyword(s):

Thermal Stability ◽

Glass Transition ◽

Phonon Scattering ◽

Vibrational Mode ◽

Low Frequency ◽

Pressure Effects

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Slow Dynamics Due to the Metal-Nonmetal Transition in Liquids

Zeitschrift für Physikalische Chemie ◽

10.1524/zpch.217.7.803.20399 ◽

2003 ◽

Vol 217 (7) ◽

pp. 803-816 ◽

Cited By ~ 1

Author(s):

Makoto Yao ◽

Hirotaka Kohno ◽

Hiroaki Kajikawa

Keyword(s):

Relaxation Time ◽

Glass Transition ◽

Liquid Glass ◽

Sound Attenuation ◽

Slow Dynamics ◽

Anomalous Increase ◽

Relaxation Strength ◽

Transition Range ◽

Liquid Dynamics ◽

Nonmetal Transition

AbstractIt is well known that the liquid dynamics slows down on approaching the liquid-gas critical point or the liquid-glass transition. Recently we have found by the sound attenuation measurements that the metal-nonmetal (M-NM) transition also induces slow dynamics. In the M-NM transition range of expanded liquid Hg, we have observed anomalous increase in the sound attenuation due to the structural relaxation process. Assuming a simple Debye-type relaxation, we have estimated that the relaxation time should be of the order of nanoseconds and revealed that the relaxation strength has a broad maximum in the M-NM transition range. Moreover, two types of anomalies have been observed also in the semiconductor-metal (S-M) transition range of liquid Te-Se mixtures. We present the recent experimental results of the sound attenuation measurements and discuss briefly the mechanisms of the slow dynamics in the metal-nonmetal transition range of liquids.

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