How Does Thermal Poling Produce Interstitial Molecular Oxygen in Silicate Glasses?

• Published in: Journal of physical chemistry. C Vol. 119; no. 30; pp. 17298 - 17307
• Main Authors: Redkov, Alexey V, Melehin, Vladimir G, Lipovskii, Andrey A
• Format: Journal Article
• Language: English
• Published: American Chemical Society 30.07.2015
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.5b04513

Thermal poling of glasses induces structural and compositional modification and breaks central symmetry of these initially isotropic media. In spite of numerous experimental data accumulated, little is known about the processes occurring in soft glasses under this processing. We use micro-Raman technique to study the formation of interstitial molecular oxygen and structural modification of the subsurface layer of a soda-lime silicate glass in the course of thermal poling. The presence of O2 is demonstrated in cation-depleted subanodic region of the glass, the thickness of which depends on the charge passed during the poling procedure and, in our experiments, reaches one micron. O2 concentration in this layer is independent of the charge passed and is on the order of 3 × 1020 cm–3 being maximal in anodic surface craters arising because of poling current nonuniformities. O2 generation is accompanied by an increase in the concentration of three-membered Si–O rings in the modified region of the glass matrix. The ways of nonbridging oxygen recombination are discussed and proposed as the main mechanism of the interstitial O2 formation.