New Paradigm of Glass Structure and Physicochemical Essence of Glass Transition

2008 ◽  
Vol 39-40 ◽  
pp. 123-128 ◽  
Author(s):  
Victor Minaev ◽  
Igor Terashkevich ◽  
Sergey Timoshenkov ◽  
Victor Kalugin ◽  
Sergey Novikov
Keyword(s):  
Raman Spectroscopy ◽  
Glass Transition ◽  
Glass Structure ◽  
Transition Process ◽  
New Paradigm ◽  
Chemical Substances ◽  
X Ray ◽  
Translation Symmetry ◽  
Numerous Data ◽  
Polymorphous Modifications

The new conception of the polymeric-polymorphoid structure of glass and glassforming liquid of individual chemical substances (ICS) is presented. The analysis of numerous data of X-ray diffractometry, DSC, Raman spectroscopy etc. shows that such glassforming ICS as SiO2, GeO2. H2O, Se, GeS2, GeSe2, As2S3, AsSe, BeCl2 and other are the copolymers of the structural fragments (polymorphoids) having no translation symmetry of two (or more) polymorphous modifications (PM) of these substances. The physicochemical essence of glass transition process is discussed.

Structural and Physical Characterization of Li2O:P2O5:MO3 (M = Cr2, Mo, W) Ion Conducting Glasses

1992 ◽  
Vol 293 ◽  
Author(s):  
B.V.R. Chowdari ◽  
K.L. Tan ◽  
W.T. Chia
Keyword(s):  
Raman Spectroscopy ◽  
Glass Transition ◽  
Transition Temperature ◽  
Photoelectron Spectroscopy ◽  
Oxygen Species ◽  
X Ray ◽  
Ion Conducting ◽  
Phosphate Groups ◽  
Glass Compositions

AbstractThe conductivity of the Li2O:P2O5:MO3 (M = Cr2, Mo, W) glasses increases as P2O5 is progressively substituted by MO3 and as the Li2O content increases. Amongst the glass compositions studied, the 0.50Li2O:0.20P2O5:0.30WO3 glass has the highest conductivity at 25°C of 2. 1×10−6 ×−1 cm−1. The glass transition temperature of the glasses increases initially with network former substitution, reaches a maximum at around MO3/P2O5 = 1, and decreases with further substitution. X-ray photoelectron spectroscopy reveals the presence of M ions in more than one oxidation state and oxygen species such as P=O, P-O-P, P-O, M-O-M, M-O and P-O-M. Raman spectroscopy shows that the Li2O:P2O5:MoO3 and Li2O:P2O5:WO3 glasses consist of PO4, MoO4 (WO4) and MoO6 (WO6) polyhedra while the Li2O:P2O5:Cr2O3 glasses consist of the PO4 and CrO6 polyhedra only. The phosphate groups are preferentially modified by Li2O in comparison with the tungstate, molybdate and chromate groups. The increasing number of non-bridging oxygen atoms per phosphate group may be related to the increasing conductivity with the progressive substitution of MO3 for P2O5.

The Evolution of Activation Field with Temperature in Ferroelectric Copolymer of Vinylidene Fluoride and Trifluoroethylene Films

2013 ◽  
Vol 785-786 ◽  
pp. 761-766
Author(s):  
Lin Jiang ◽  
Xiang Jian Meng ◽  
X. L. Zhao ◽  
B. B. Tian ◽  
B. L. Liu ◽  
...  
Keyword(s):  
Thin Film ◽  
Glass Transition ◽  
Vinylidene Fluoride ◽  
Ferroelectric Thin Film ◽  
Transition Process ◽  
The Other ◽  
Polarization Reversal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polyimide Substrate

Vinylidene fluoride and trifluoroethylene [P(VDF-TrFE)] ferroelectric thin film was spin-coated on Au-coated polyimide substrate and its polarization reversal was investigated by analyzing the evolution of activation field (α) with temperature. Although α is nearly a constant between 300 and 330 K, it increases linearly when temperature rates between 200 and 230 K, and between 230 and 300 K. On the other hand, the intensity of X-ray diffraction for P(VDF-TrFE) films from 200 to 330 K indicates that glass-transition process plays a significant role in both the microstructure and the polarization reversal of P(VDF-TrFE) copolymer.

Investigation of glass structure in As(Sb)-S(Se)-I systems by the methods of Raman spectroscopy and x-ray diffraction

1995 ◽  
Author(s):  
V. M. Rubish ◽  
I. Yurkin ◽  
V. Malesh ◽  
Vassyl' Fedelesh ◽  
M. L. Trunov ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Glass Structure ◽  
X Ray Diffraction ◽  
X Ray

PHYSICAL PROPERTIES OF TELLURITE GLASSES PREPARED UNDER DIFFERENT THERMAL HISTORIES

2010 ◽  
Vol 24 (06) ◽  
pp. 527-537
Author(s):  
E. B. ARAÚJO ◽  
E. IDALGO ◽  
A. P. A. MORAES ◽  
A. G. SOUZA FILHO ◽  
J. MENDES FILHO
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
Glass Transition ◽  
Tellurite Glasses ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
In Situ Crystallization ◽  
Thermal Histories

Tellurite glasses were prepared with identical 20 Li 2 O -80 TeO 2 nominal compositions but with different thermal histories. Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Raman spectroscopy techniques were used to understand the effects of the thermal histories on the thermal and structural properties of these glasses. It was observed that investigated properties depend strongly on the thermal histories. DSC results suggested that annealing immediately after quenching at temperatures around the glass transition temperature (Tg) and for longer times is favorable for producing local ordered regions in the glass without necessarily increasing the number of nuclei. XRD results revealed the crystallization of the γ- TeO 2, α- TeO 2 and α- Li 2 Te 2 O 5 phases in both studied glasses. Raman spectroscopy revealed the mestastable character of the γ- TeO 2 crystalline phase, while the α- TeO 2 and α- Li 2 Te 2 O 5 crystalline phases persisted up to the final stages of the in-situ crystallization.

scholarly journals New Interpretation of X-ray Diffraction Pattern of Vitreous Silica

Ceramics ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 83-96
Author(s):  
Shangcong Cheng
Keyword(s):  
Glass Transition ◽  
Diffraction Pattern ◽  
Random Network ◽  
Transition Process ◽  
Vitreous Silica ◽  
X Ray Diffraction ◽  
Broad Ring ◽  
X Ray ◽  
New Interpretation ◽  
Diffraction Patterns

The striking feature of X-ray diffraction pattern of vitreous silica is that the center of its intense but broad ring is located at nearly the same position as the strongest diffraction ring of β-cristobalite. Two fundamentally different explanations to the diffraction patterns were appeared about 90 years ago, one based on the smallest crystals of β-cristobalite and the other based on the non-crystalline continuous random network. This work briefly outlines the facts supporting and objecting these two hypotheses, and aims to present a new interpretation based on a medium-range ordering structure on the facets of clusters formed in the glass transition process. It will be shown that the new interpretation provides a more satisfactory explanation of the diffraction pattern and physical properties of silica glass, and offers considerable valuable information regarding the nature of glass and glass transition.

Raman spectroscopy and X-ray diffraction of lithium niobate at temperatures up to 1300○-4.80pt○C

2005 ◽  
Vol 126 ◽  
pp. 101-105 ◽  
Author(s):  
B. Moulin ◽  
L. Hennet ◽  
D. Thiaudière ◽  
P. Melin ◽  
P. Simon
Keyword(s):  
Raman Spectroscopy ◽  
Lithium Niobate ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Use of WetSEM® capsules for convenient multimodal scanning electron microscopy, energy dispersive X-ray analysis, and micro Raman spectroscopy characterisation of technetium oxides

2021 ◽  
Author(s):  
D. J. Bailey ◽  
M. C. Stennett ◽  
J. Heo ◽  
N. C. Hyatt
Keyword(s):  
Raman Spectroscopy ◽  
Low Cost ◽  
Powder Materials ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Hazard And Risk ◽  
Sem Imaging ◽  
General User ◽  
532 Nm

AbstractSEM–EDX and Raman spectroscopy analysis of radioactive compounds is often restricted to dedicated instrumentation, within radiological working areas, to manage the hazard and risk of contamination. Here, we demonstrate application of WetSEM® capsules for containment of technetium powder materials, enabling routine multimodal characterisation with general user instrumentation, outside of a controlled radiological working area. The electron transparent membrane of WetSEM® capsules enables SEM imaging of submicron non-conducting technetium powders and acquisition of Tc Lα X-ray emission, using a low cost desktop SEM–EDX system, as well as acquisition of good quality μ-Raman spectra using a 532 nm laser.

scholarly journals Structural and Raman Vibrational Studies ofCeO2-Bi2O3Oxide System

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
L. Bourja ◽  
B. Bakiz ◽  
A. Benlhachemi ◽  
M. Ezahri ◽  
J. C. Valmalette ◽  
...  
Keyword(s):  
Solid Solution ◽  
Raman Spectroscopy ◽  
Phase Changes ◽  
Phase System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vibrational Studies ◽  
Coprecipitation Route

A series of ceramics samples belonging to theCeO2-Bi2O3phase system have been prepared via a coprecipitation route. The crystallized phases were obtained by heating the solid precursors at600∘Cfor 6 hours, then quenching the samples. X-ray diffraction analyses show that forx<0.20a solid solutionCe1−xBixO2−x/2with fluorine structure is formed. For x ranging between 0.25 and 0.7, a tetragonalβ′phase coexisting with the FCC solid solution is observed. For x ranging between 0.8 and 0.9, a new tetragonalβphase appears. Theβ′phase is postulated to be a superstructure of theβphase. Finally, close tox=1, the classical monoclinicα Bi2O3structure is observed. Raman spectroscopy confirms the existence of the phase changes as x varies between 0 and 1.

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