Infrared Spectroscopy of Glasses

Kamitsos, E. I.

doi:10.1002/9781119051862.ch2

Cited by 15 publications

(14 citation statements)

References 72 publications

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“…Reflectance spectra were measured separately in the far-and mid-IR ranges by collecting and then averaging 2000 and 400 scans, respectively, and then merging the two averages to form a continuous spectrum in the range 30−7000 cm −1 . Analysis of the reflectance spectrum of TeO 2 glass by Kramers−Kronig transformation 33 yielded the absorption coefficient spectrum, α(ν), presented in this work. 23 a TeO 2 fragment was added either to each of the threecoordinated tellurium atoms (TeO 3 ) or to each of the terminal oxygen atoms in order to produce initial (TeO 2 ) 4 clusters.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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On the Absence of Doubly Bonded Te═O Groups in TeO₂ Glass

et al. 2020

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Tellurium oxide clusters (TeO 2 ) 6 were investigated through density functional theory to gain information on the structure of TeO 2 glass. Among a large number of stable conformers studied, a cyclic, nonsymmetric structure was optimized without terminal TeO double bonds. The dimer of this structure, (TeO 2 ) 12 , gives calculated Raman and infrared spectra in very good agreement with the experimental ones, with its total pair distribution function being also in agreement with results of neutron and high-energy X-ray diffraction studies. The (TeO 2 ) 12 cluster consists mainly of TeO 4 units connected by asymmetric and nearly symmetric Te−O−Te bridges as in γ-TeO 2 and involves also edge-sharing through double-oxygen Te−O 2 −Te bridges as in the β-TeO 2 polymorph. The optimized cluster structure is slightly unstable compared to the calculated global minimum structure, suggesting a kinetically stable product similar to its corresponding experimental TeO 2 glass.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

On the Absence of Doubly Bonded Te═O Groups in TeO₂ Glass

et al. 2020

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“…Reflectance spectra were measured separately in the far-and mid-IR ranges and then merged to form a continuous spectrum in the range 30-7000 cm -1 . Analysis of the reflectance spectra by Kramers-Kronig transformation yielded the absorption coefficient spectra, a(m) [21]. The estimated error in infrared band position was ± 2 cm -1 .…”

Section: Glass Characterizationmentioning

confidence: 99%

Mechanism of hopping conduction in Be–Fe–Al–Te–O semiconducting glasses and glass–ceramics

et al. 2022

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Electrical properties of beryllium-alumino-tellurite glasses and glass–ceramics doped with iron ions were studied using impedance spectroscopy. The conductivity was measured over a wide frequency range from 10 mHz to 1 MHz and the temperature range from 213 to 473 K. The D.C. conductivity values showed a correlation with the Fe-ion concentration and ratio of iron ions on different valence states in the samples. On the basis of Jonscher universal dielectric response the temperature dependence of conductivity parameters were determined and compared to theoretical models collected by Elliott. In glasses, the conduction process was found to be due to the overlap polaron tunneling while in glass–ceramics the quantum mechanical tunneling between semiconducting crystallites of iron oxides is proposed. The D.C. conductivity was found not to follow Arrhenius relation. The Schnakenberg model was used to analyze the conductivity behavior and the polaron hopping energy and disorder energy were estimated. Additionally, the correlation between alumina dissolution and basicity of the melts was observed.

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“…Reflectance spectra were measured separately in the far- and mid-IR ranges and then merged to form a continuous spectrum in the range 30–7000 cm –1 . Analysis of the reflectance spectra by Kramers–Krönig transformation yielded the absorption coefficient spectra, α ( ν ), presented in this work.…”

Section: Experimental Sectionmentioning

confidence: 99%

Short-Range Structure, Thermal and Elastic Properties of Binary and Ternary Tellurite Glasses

et al. 2019

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Glasses Al2/3O–TeO2, ZnO–TeO2 and R2/3O–ZnO–TeO2 (R = Al, B) were prepared by melting in Pt crucibles and studied for correlations between structure and thermal as well as mechanical properties, whereby the glass composition is varied to tailor the short-range speciation of tellurite, aluminate, and borate groups. The glass structure was studied by Raman and infrared spectroscopy analyses, and the measured properties include glass-transition temperature (T g), density (ρ), and ultrasonic longitudinal (V L) and transverse (V T) velocities. In addition, atomic packing density (C g), elastic moduli, and Poisson’s ratio (σ) were evaluated from the measured properties. It was found that Al2/3O leads to cross-linked alumino-tellurite networks by strong Te–O–Al bonds, which cause a profound enhancement in T g. The influence of ZnO and B2/3O on T g is relatively smaller due to the weaker cross-linking effects of ZnO4 tetrahedra and of Te···O–B bonds. Short-range bonding characteristics, interatomic bonding energy differences, and atomic packing density were found to have a strong effect on V T and mostly on the V L sound velocity. The combined effects of structure and bonding are nicely expressed in the composition dependence of Poisson’s ratio; it exhibits decreasing trends with Al2/3O content in the binary and ternary glasses studied here, but increasing trends with ZnO and B2/3O additions in glasses ZnO–TeO2 and B2/3O–ZnO–TeO2, respectively. The results for Poisson’s ratio and atomic packing density for the studied glasses were found to fit nicely in the global σ versus C g correlation established previously for a range of glasses not including tellurites so far. Finally, the sound velocities and Poisson’s ratio of pure TeO2 glass were determined for the first time and found to differ markedly from those in the literature for TeO2 glass melted in alumina crucible; this is because the latter glass is highly doped by Al2O3 leached from the alumina crucible.

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Infrared Spectroscopy of Glasses

Cited by 15 publications

References 72 publications

On the Absence of Doubly Bonded Te═O Groups in TeO₂ Glass

On the Absence of Doubly Bonded Te═O Groups in TeO₂ Glass

Mechanism of hopping conduction in Be–Fe–Al–Te–O semiconducting glasses and glass–ceramics

Short-Range Structure, Thermal and Elastic Properties of Binary and Ternary Tellurite Glasses

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Infrared Spectroscopy of Glasses

Cited by 15 publications

References 72 publications

On the Absence of Doubly Bonded Te═O Groups in TeO2 Glass

On the Absence of Doubly Bonded Te═O Groups in TeO2 Glass

Mechanism of hopping conduction in Be–Fe–Al–Te–O semiconducting glasses and glass–ceramics

Short-Range Structure, Thermal and Elastic Properties of Binary and Ternary Tellurite Glasses

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Product

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On the Absence of Doubly Bonded Te═O Groups in TeO₂ Glass

On the Absence of Doubly Bonded Te═O Groups in TeO₂ Glass