Fabrication, physical, thermal and optical properties of oxyfluoride glasses doped with rare earth oxides

The impact of the addition of different rare earth oxides such as Ho2O3, Nd2O3, Sm2O3, and Yb2O3 on the physical, structural, thermal, and optical properties of the prepared NaO2–CaF2 bismuth borate glasses was examined. FTIR spectra of the glass samples were performed in the range of 400–4000 cm−1. UV–visible–NIR absorption spectral measurements were carried out of the range 200–2500 nm. Differential thermal analysis and the thermal expansion data of the prepared glasses were measured. FTIR the spectra of the proposed glasses showed that the rare earth mainly led to formation of BiO6 and BO4 groups as the intensity of peaks related to them increase with the addition of rare earth. An increase in the density of the glasses was noticed with the substitution of Na2O by rare earth oxide. Addition of mol% Yb2O3 to glasses leads to increase in the ionic concentration, polaron radius and interionic distance of glasses and decrease the field strength and density. The obtained metallization values fluctuated between 0.3153 and 0.3570. The molar polarizability (αm) and molar electronic polarizability (αme) were enhanced with the increase of Yb2O3 content. The values of dielectric constants (e and eopt) were decreased with in Sm2O3 and Nd2O3 glasses, whereas they increased in Ho2O3 glass. The Ts values were increased with the increase of rare earth oxide and Yb2O3 content. The optical energy gap decreases with the addition of rare earth oxide and Yb2O3 concentration. The refractive indices of all studied glasses are relatively high, thus one can concluded that the present glasses can be used as a candidate for optoelectronic, photoelectronic, and communications instruments and non-linear optical devices. The addition of Yb ions leads to decrease the emission and excitation intensity which may be attributed to concentration quenching effect.