Thermostimulated nonradiative recombination of impurity color centers in sodium silicate glasses co-activated by terbium and iron

The extent of the recharging of Tb³⁺ and Fe³⁺ ions with the formation of impurity (Tb³⁺)⁺ and (Fe³⁺)⁺ ions is increased in Na₂O · 3SiO₂ glasses activated by Tb³⁺ and Fe³⁺ ions as the concentration of Fe³⁺ is increased. Here, the amount of intrinsic electro color centers formed under the action of UV radiation decreases and the light-sum of the thermally stimulated luminescence in the 300-700°K interval associated with the decay of these electron centers also fails sharply. Over the 300-700K interval, induced absorption in both the intrinsic and impurity color centers is fully annealed. The results obtained on thermally stimulated recombination and relaxation of the induced absorption in these glasses can be explained by the occurence of effective nonradiative recombination between the (Fe³⁺)^- and (Tb³⁺)⁺ cneters.