Raman spectra of K2O–B2O3 glasses and melts

Akagi, Ryuichi; Ohtori, Norikazu; Umesaki, Norimasa

doi:10.1016/s0022-3093(01)00752-9

Cited by 106 publications

(72 citation statements)

References 9 publications

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“…Figure 5 shows the Raman spectra and related Gaussian deconvoluted bands of non-crystalline CaO-SiO2-B2O3 within a 400 to 1 600 cm -1 range of Raman shift. These Raman spectra have been identified from appropriate references [34][35][36][37][38][39][40][41] and are listed in Table 2. Owing to the complicated structure of boron oxide, the possibility of a borate structure existing within the CaO-SiO2 system was investigated; and an annular metaborate group, chain-type metaborate group, pyroborate group and six-membered borate ring were all considered in the present study.…”

Section: Effect Of Temperature and Composition On Thermal Conductivitymentioning

confidence: 99%

Relationship between Molten Oxide Structure and Thermal Conductivity in the CaO–SiO2–B2O3 System

Kim

Morita

2014

ISIJ Int.

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Using a transient hot-wire method, the thermal conductivity of the CaO-SiO2-B2O3 mold flux system was measured. The effects of temperature, BO1.5 concentration and basicity on the thermal conductivity were considered, along with structural investigation by Raman spectroscopy. It was found that the addition of boron oxide caused both a decrement and increment of thermal conductivity, depending on the basicity. These conflicting effects on thermal conductivity were considered to be caused by the following two different behaviors in the oxide melts. Boron oxide is incorporated into silicate networks at a lower basicity, while it tends to form borate networks at higher CaO/SiO2 ratios. In the case of basicity dependency, thermal conductivity initially decreases or remains constant with increasing CaO/SiO2 ratio in regions of low basicity, but increases when the CaO/SiO2 ratio is higher than 1.15. Due to the incorporated state of boron oxide in silicate networks at low basicity, the thermal conductivity is likely to be predominantly affected by the silicate networks. However, at a relatively high CaO/SiO2 ratio, an increase in chain-type metaborate was observed through Raman spectroscopy; this structural change in borate being responsible for the increment in thermal conductivity with higher basicity. Finally, the apparent activation energy of thermal conductivity was calculated, and was found to be reduced by the addition of boron oxide.

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Section: Effect Of Temperature and Composition On Thermal Conductivitymentioning

confidence: 99%

Relationship between Molten Oxide Structure and Thermal Conductivity in the CaO–SiO2–B2O3 System

Kim

Morita

2014

ISIJ Int.

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“…The result of this effect is that a simulated glass reflects the quasiequilibrium structure arrested at high temperatures. As shown by statistical-mechanical calculations 36 and by spectroscopic techniques, such as NMR, 37 infrared, 38 x-ray diffraction, 39 and Raman, 40 the NBO-containing triangular units of modified borate glasses are favored at high temperatures at the expense of the BØ 4 − tetrahedra. A similar effect of temperature was found in a recent MD simulation of a B 2 O 3 glass, in the sense that the maximum fraction of boroxol rings ͑ca.…”

Section: A Composition and Temperature Dependence Of The Short-rangementioning

confidence: 99%

“…This finding is in accord with the high-temperature Raman study of Akagi et al on K borate glasses. 40 They have demonstrated that the Raman profiles of the x = 0.3 glass/ melt are much more sensitive to temperature changes than those of the x = 0.2 glass/ melt. It is clear from the above discussion that a comparison of the X 4 data on laboratory glasses from MD simulations with those from NMR spectroscopy should be made with caution.…”

Section: A Composition and Temperature Dependence Of The Short-rangementioning

confidence: 99%

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Composition and temperature dependence of cesium-borate glasses by molecular dynamics

Vegiri

Varsamis

Kamitsos

2005

The Journal of Chemical Physics

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The structural aspects of xCs 2 O-͑1−x͒B 2 O 3 glasses have been investigated by molecular dynamics as functions of Cs 2 O content ͑x = 0.2, 0.3, and 0.4͒ and temperature ͑T = 300 and 1250 K͒. The tetrahedral ͑BØ 4 − ͒ and triangular ͑BØ 3 ,BØ 2 O − , and BØO 2 2− ͒ short-range order borate units were found to be the structure-building entities of the simulated glasses ͓Ø=bridging oxygen ͑BO͒ and O − =nonbridging oxygen ͑NBO͒ atom͔. The increase of Cs 2 O content results in the progressive increase of the NBO-containing triangle population at the expense of the BØ 4 − tetrahedral units. The same effect is caused by temperature increase at a fixed Cs 2 O content, and this was associated with the "fragile" characteristics of alkali borate glasses. A comparison of simulated Cs and Li borates showed very similar structures at x = 0.2, but dissimilar ones when the alkali content exceeds this composition. In particular, for x Ͼ 0.2 Cs borates exhibit a preference for NBO formation relative to Li borates. Differences in the microstructure of sites hosting Cs ions were found, and this permits their classification into bridging ͑b type͒ and nonbridging type ͑nb type͒ of sites. b-type sites consist exclusively of BO atoms, while both BO and NBO atoms participate in nb-type sites. These differences in Cs-site local bonding characteristics were found to be reflected on the Cs-O͑site͒ vibration frequencies. Also, the computed Cs-O vibrational responses for simulated Cs borates were found to compare well with experimental far-infrared spectra.

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“…Note that the band intensities of the spectra were reduced using the Bose-Einstein population factor. 8,9 To get a deeper a͒ Author to whom correspondence should be addressed. Electronic mail: cristiane.nascimento@uclouvain.be.…”

mentioning

confidence: 99%

Structural, dielectric, and optical properties of yttrium calcium borate glasses

Santos

Meneses²,

Echegut³

et al. 2009

Applied Physics Letters

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Surface rippling on bulk metallic glass under nanosecond pulse laser ablation Appl. Phys. Lett. 99, 191902 (2011) Construction of a disorder variable from Steinhardt order parameters in binary mixtures at high densities in three dimensions J. Chem. Phys. 135, 174109 (2011) Fragility of iron-based glasses Appl. Phys. Lett. 99, 161902 (2011) Communication: Are metallic glasses different from other glasses? A closer look at their high frequency dynamics J. Chem. Phys. 135, 101101 (2011) Temperature dependence of the thermoplastic formability in bulk metallic glasses

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Raman spectra of K2O–B2O3 glasses and melts

Cited by 106 publications

References 9 publications

Relationship between Molten Oxide Structure and Thermal Conductivity in the CaO–SiO2–B2O3 System

Relationship between Molten Oxide Structure and Thermal Conductivity in the CaO–SiO2–B2O3 System

Composition and temperature dependence of cesium-borate glasses by molecular dynamics

Structural, dielectric, and optical properties of yttrium calcium borate glasses

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