Structural, optical and dielectric characterization of niobium lithium tetraborate glasses doped praseodymium

Abstract Glasses with compositions (100-x) Li 2 B 4 O 7 -x Nb 2 O 5 doped 1 mol% Pr 6 O 11 (where x = 15, 25 and 35 mol%) were prepared. The glass nature of the present samples was established by X-ray diffraction (XRD) which is confirmed by differential thermal analysis (DTA) study. The infrared absorption spectra indicate that the structural units of the present samples are made up of BO 3 , BO 4, NbO 4 and NbO 6 . From the intensities of some optical absorption bands, Judd-Ofelt parameters Ω λ (λ = 2, 4, 6) have been evaluated. The variations in some physical properties such as the density (ρ), molar volume (V M ), optical band gap (E g ) and Urbach energy (E 0 ) have correlated with structural changes in the glass samples. Measurements of the dielectric constant, dielectric loss and ac conductivity as a function of frequency (120 Hz − 100 kHz) and temperature (310–670 K) have also reported.