ИСТИНА

properties of crystalline fluorides and oxide glasses, which make them promising for new laser materials when the cubic phase of PbF2 in GCs is activated by rare-earth (RE) ions. 7-10 mol% of RE fluoride is enough for the cubic phase stabilization. As stabilizing agents we used La(Lu)F3 which did not generated luminescence. NdF3 was used as an activator which formed efficient luminescence centers in GCs. The 67PbF2?30B2O3-3REF3 glasses in which REF3 consisted of 0.2-3 mol% of NdF3 + 0-2.8 mol% LaF3(or LuF3) have been synthesized. DTA showed strong difference in characteristic temperatures and thermal effects depending on Nd/La ratio. GCs were obtained by the controlled crystallization of glasses. The total RE concentration in the crystalline phase varied from 11-12 at% for Pb(1-x)La/Nd(x)F(2+x) to 17-18 at% for Pb(1-x)Lu/Nd(x)F(2+x). Comparison of luminescence spectra of glasses, GCs and crystalline samples showed that there is a splitting of the 0-0 line of the interstark of 4F3/2?4I9/2 transition in Nd3+ ion in the case of the GCs made from co-doped glasses, which is observed in crystals. Thus, it has been demonstrated that it was possible to stabilize a cubic phase based on PbF2 simultaneously by several RE dopants and to obtain GCs with a crystalline phase in which the concentration quenching was reduced compared to GCs doped with a single activator. Supported by the grant 17.1.18.0026.01 (10.4702.2017/BC).