Investigation of Spectral Properties of Potassium Aluminoborate Glasses Doped with Chromium

Spectral properties of potassium aluminoborate glasses activated by various concentrations of trivalent chromium compounds are studied. The temperatures of glass transition (434°C) and bulk crystallization of the glass matrix (600°C) are determined. The heat treatment of the glass at the crystallization temperature results in the appearance of intensive narrow luminescence bands in the area of 685–715 nm that is connected with the crystallization of the LiAl 7 B 4 O 17 :Cr 3+ phase in the glass matrix; in this phase chromium is located in a highly symmetrical octahedral surrounding. Concentration dependences of lifetime and quantum yield show the existence of the concentration luminescence quenching at increasing chromium content in the glass from 0.05 to 0.2 mol %. The maximum value of quantum yield is 30%.