Electron spin resonance in phosphate glasses containing mixed transition metal ions

Phosphate glasses containing mixed Cu²⁺/Ni²⁺ and Cu²⁺/Co²⁺ oxides have been examined. A pronounced decrease in the optical absorption at 830 nm due to the Cu²⁺ ions is observed as the CuO in the glasses is gradually replaced by NiO or CoO and the decrease is accompanied by a pronounced decrease in the strength of the electron spin resonance (ESR) signal at 9.52 GHz. By combining the ESR and optical absorption data it is concluded that the decrease in concentration of Cu²⁺ ions in phosphate glasses may be due to an oxidation-reduction mechanism between two valency states of the two different transition metals, of the form Cu²⁺+Ni⁺Cu⁺+Ni²⁺ and Cu²⁺+Co⁺Cu⁺+Co²⁺.