Electronic polarizability in silicate glasses by comparison of experimental and theoretical optical basicities

Series of multi-component glass systems of the following chemical composition SiO2-Na2O-CaO-Nd2O3 with an increasing of rare earth concentration, the effect of Nd2O3 on the optical properties of the glass systems is investigated. On the basis of the measure values of densities and refraction, Nd3+ ion concentration in glasses and several other physical properties were determined. The absorption coefficient, both direct and indirect optical energy gaps, and Urbach energy are evaluated using the absorption edge calculations. The different factors that play a role for controlling the refractive indices such as electronic polarizability, bridging and non-bridging oxygen, and optical basicity are discussed in accordance with the obtained index data. The non-crystalline phase identified basing on X-ray diffraction analysis.

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Optical and electronic polarizability investigation of Nd3+-doped soda-lime silicate glasses

Journal of Physics and Chemistry of Solids ◽

10.1016/j.jpcs.2010.03.044 ◽

2010 ◽

Vol 71 (7) ◽

pp. 965-970 ◽

Cited By ~ 79

Author(s):

P. Chimalawong ◽

J. Kaewkhao ◽

C. Kedkaew ◽

P. Limsuwan

Keyword(s):

Soda Lime ◽

Silicate Glasses ◽

Electronic Polarizability

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Direct observations of radiation-enhanced transformations in glass

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075543 ◽

1983 ◽

Vol 41 ◽

pp. 354-355

Author(s):

J. F. DeNatale ◽

D. G. Howitt

Keyword(s):

Glass Matrix ◽

Diffusion Mechanism ◽

Bubble Formation ◽

Silicate Glasses ◽

Phase Decomposition ◽

Direct Observations ◽

Thin Foils ◽

Oxygen Bubble ◽

Electron Energy Loss ◽

Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

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