Borosilicate Glasses

Youngman, Randall E.

doi:10.1002/9781118801017.ch7.6

Cited by 5 publications

(3 citation statements)

References 30 publications

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“…A narrow peak near the 0 ppm point corresponded to the BO 4 (3Si,1B) structural units (where a boron atom replaces a silicon atom) [ 73 ]. For the quenched sample, a small contribution from the BO 4 (4Si) structural units (where the tetrahedral boron atom is surrounded only by silicon atoms) was also observed at about −2 or −3 ppm [ 74 ]. The broadest peak seen at the highest chemical shift values corresponded to three coordinated boron atoms and can be decomposed into two components.…”

Section: Resultsmentioning

confidence: 99%

“…One of these components has a complex shape, with two well-defined maxima, and is located in the region of the spectrum with large chemical shifts. This component can be associated with boron that is surrounded by bridging bonds with the boron atoms, generally known as boroxol rings (BO 3 ring ), which could include other boron entities involving BO 3 –O–BO 4 bonds [ 73 , 74 ]. The second component was visually indistinguishable in the spectrum and was revealed only as a result of the decomposition of the spectrum into its components.…”

Section: Resultsmentioning

confidence: 99%

“…It has a broadened shape compared to BO 4 and is located between the BO 3ring and BO 4 (3Si,1B) lines. This component can be attributed to boron that is distributed in silicate units (generally referred to as BO 3 non-ring ) [ 73 , 74 ]. Analyzing the areas of the corresponding spectral components (percentage of structural units) for all the samples being studied showed that with an increase in the duration of the heat treatment, a decrease in the BO 4 structural units occurred, due to an increase in three coordinated structural units ( Table 3 ).…”

Section: Resultsmentioning

confidence: 99%

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Crystallization of Cristobalite in Sodium Borosilicate Glass in the Presence of Cr2O3

et al. 2023

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Glass containing chromium is a promising material for use in various modern fields of application (laser technology, optoelectronic devices, and luminescent resources). Chromium oxides are well-known nucleating agents that can cause crystallization. One of the most commonly observed crystalline phases in silicate glasses is cristobalite, which lowers their mechanical strength, leading to the destruction of the material. The objective of this investigation was to study in detail the crystallization of cristobalite in sodium borosilicate glass in the presence of 2 mol% Cr2O3, depending on the thermal history of the glass. The glass was studied using XRD, SEM, EPR, FTIR-spectroscopy, XPS, and solid-state NMR. Eskolaite, α-Cr2O3, which had crystallized in this glass, stimulated the bulk crystallization of cristobalite at 550 °C after isothermally treating it for 72 h, due to the phase-separated structure of the glass with its interpenetrating phase morphology. Polytypism, resulting in the incorporation of alkalis into the cristobalite structure, was observed. Cr2O3 causes the catalytic crystallization of cristobalite at an extremely low temperature, which is at lower concentrations and temperatures than in glass containing Fe2O3 with a similar composition. The crystal growth rate and the incubation time for the crystallization of cristobalite were roughly estimated.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%