Thermal expansion of silico-phosphate glasses with small additions of Fe sub(2)O sub(3): EPR and dilatometric studies

• Published in: Journal of materials science Vol. 19; no. 11; pp. 3620 - 3625
• Main Authors: Azzoni, C B, Del Nero, G L, Krajewski, A, Ravaglioli, A
• Format: Journal Article
• Language: English
• Published: 01.01.1984
• ISSN: 0022-2461

Electron paramagnetic resonance (EPR) and dilatometric measurements in phosphosilicate glass have been made in order to elucidate an anomalous trend to the linear thermal expansion coefficient beta when Fe sub(2)O sub(3) was added to the composition. The g approximately equals 2 and g sub(eff) approximately equals 4.27 EPR lines were attributed, to undistorted and octahedrally coordinated Fe super(3+) ions, and to Fe super(3+) ions in low symmetry (rhombic) sites. The Fe super(3+) ion distribution in the network at different temperatures was explained by a model of chemical insertion and it has been proved that the Fe super(3+) ions have two kinds of role as network modifiers. A relationship was found between beta and the amounts of Fe sub(2)O sub(3) added in the range 0 to 12 wt %.