Optimization of the matrix compositions and properties of silver-free photochromic glasses

Mashir, Yu. I.

doi:10.1007/bf02782536

Cited by 2 publications

(4 citation statements)

References 1 publication

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“…The Al do not show 5 Al in the surface, but do show the formation of 3 Al. Upon exposure to water, the change in 3 Al into 4 Al is almost complete for all of the compositions, as shown in Figure 11.…”

Section: Exposure To Watermentioning

confidence: 82%

“…Soda-lime alumino-borosilicate glasses have found applications in many fields [1][2][3][4] and there is renewed interest in the structure and properties of these glasses. [5][6][7][8][9][10][11][12][13][14] In a recent paper, 15 the bulk structure of aluminoborosilicate glasses containing 10%-20% Ca and Na modifiers was explored using molecular dynamics simulations of systems containing~20 000 atoms.…”

Section: Introductionmentioning

confidence: 99%

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Simulations of the surfaces of soda lime aluminoborosilicate glasses exposed to water

Garofalini

Urraca

2017

J Am Ceram Soc

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Molecular dynamics simulations of 7 compositionally different sodium calcium alumino‐borosilicate glasses showed formation of 4B and 5Al more consistent with experimental data without compromising the other structural features that match experimental results observed in recent simulations of these glasses. Analysis of the dry surfaces of these glasses show a lack of 4B in the top 5‐6 Å of the surface in comparison to the bulk concentration for all glasses and no 5Al. Upon exposure to water, the simulations show that the 3B in the top 5‐6 Å of the glasses are preferentially attacked, decreasing the number of B bonds to O originally from the glass, indicating a change in the glass network. Inclusion of all B–O bonds in the top 5‐6 Å (i.e., including O from water) shows a decrease in 3B but an increase in 4B that is consistent with NEXAFS analysis, which the simulations show are hydroxylated. There is an increase in the concentration of 3Al in the dry surface in comparison to the bulk, but exposure to water converts almost all of these 3Al to 4Al. Hydroxyl concentrations vary from 2.6/nm2 to 4.1/nm2, with SiOH and BOH dominating these surface hydroxyls. Upon exposure to water, network linkages to B are preferentially ruptured. This, and the preferential loss of the nonbridging oxygen sites attached to Na, provide atomistic evidence of the initial stages of removal of B and Na from glass surfaces exposed to water.

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Section: Exposure To Watermentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Simulations of the surfaces of soda lime aluminoborosilicate glasses exposed to water

Garofalini

Urraca

2017

J Am Ceram Soc

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Section: Introductionmentioning

confidence: 99%

“…Aluminoborosilicate glasses are widely used in many technologies such as commercial glasses, fiber glass, photochromic glasses, glazes, and the sequestration of radioactive waste. [1][2][3][4][5] For instance, E-Glass is a type of alumino-borosilicate glass with a particular range of compositions and E-glass fibers are used in composites for their ability to maintain their strength properties over a wide range of conditions. [6][7][8] Extensive effort has been made to document the properties of various alumino-borosilicate glass compositions, as well as efforts to explore the structure of alumino-borosilicate glasses.…”

Section: Introductionmentioning

confidence: 99%

Local structure of network modifier to network former ions in soda‐lime alumino‐borosilicate glasses

Garofalini

2016

J Am Ceram Soc.

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The structure of soda‐lime alumino‐borosilicate glass was studied using molecular dynamics simulations of samples of varying compositions containing ~20 000 atoms each. Pair distribution functions (PDFs) of cations to oxygen were used for comparison to available experimental data to evaluate consistency between simulations and experiment. Additional PDFs and coordination of the network forming cations (Al/B/Si) to network modifiers (Ca/Na) were examined, which is difficult to measure experimentally. The results are consistent with available experimental data regarding cation‐oxygen bond lengths and network former to oxygen coordination numbers. Si and Al are predominantly 4‐coordinated, with a small concentration of overcoordinated species similar to experimental data. B varied as 3‐coordinated, BO3, and 4‐coordinated, BO4, as a function of the amount of Ca2+ and Na+ present, the ratio of Al2O3 to B2O3, and the fictive temperature of the sample, similar to experimental data. The simulations provide new information regarding the locations on the network modifiers to the +3 cations, Al and B. For instance, one Al ion can have multiple Na within 4 Å, but also the Na can be within 4 Å of several +3 cations. Such results would indicate a greater complexity of local structure that goes beyond the stoichiometric one +1 modifier ion near one +3 network former or one +2 modifier near two +3 formers in tetrahedral sites.

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Optimization of the matrix compositions and properties of silver-free photochromic glasses

Cited by 2 publications

References 1 publication

Simulations of the surfaces of soda lime aluminoborosilicate glasses exposed to water

Simulations of the surfaces of soda lime aluminoborosilicate glasses exposed to water

Local structure of network modifier to network former ions in soda‐lime alumino‐borosilicate glasses

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