The goal of this work was to investigate the influence of rare earth ions such as Tm3+, Yb3+ on physico-chemical properies
of tellurite glass from the TeO2-WO3-PbO-PbF2-Na2O system. The thermal characteristic of tellurite glass Tm3+, Yb3+ doped have been
presented. The effect of the glass crystallization on thermal stability of the glass and crystallizing phases formed upon heat treatment were
investigated by DTA/DSC/, XRD methods. The spectral dependence of ellipsometric angles of the tellurite glass samples, have been studied.
The influence of ions of rare earth elements, i.e. Tm 3+ and Yb3+, onto changes of refractive index of glass P1 (without RE admixture) were
examined. The optical measurements were conducted on Woollam M2000 spectroscopic ellipsometer, in spectral range of 190-1700 nm.