Transition metal ions in silicate melts—I. Manganese in sodium silicate melts

Optical absorption spectra obtained on glasses quenched from sodium silicate melts show Mn³⁺ to be the dominant species for melts heated in air and Mn²⁺ to be the dominant species for melts heated at Po₂ = 10^?17 bar. The absorption spectrum of Mn³⁺ consists of an intense band at 20,000cm^?1 with a 15,000cm^?1 satellite possibly arising from the Jahn-Teller effect. The independence of the spectrum from melt composition and the high band intensity is offered as evidence for a distinct Mn³⁺ complex in the melt. The spectrum of Mn²⁺ is weak and many expected bands are not observed. A two-band luminescence spectrum from Mn²⁺ has been tentatively interpreted as due to Mn²⁺ in interstitial sites in the network and Mn²⁺ coordinated by non-bridging oxygens.