Effect of CeO ₂ on the Glass Structure of Sodium Germanate Glasses

Abstract

Germanate glasses have potential applications as optical fibers. Materials doped with rare earth ions are good candidates for optical, lasing, and magnetic applications. Based on the ternary system, CeO 2 – Na 2 O – GeO 2 a series of six glasses were fabricated using powder fusion, and varying the Na 2 O content from 0 to 45 mol%, and a CeO 2 content constant at 3 mol%. The glasses were analyzed by FT ‐ IR , Raman and X‐ray photoelectron (XPS) spectroscopies to obtain information about the glass structure, cerium oxidation's state and how it is introduced in the glass network. FT ‐ IR and Raman spectra revealed the presence of GeO 6 and GeO 4 groups as well as Q 2 and Q 3 units in the glasses with alkali low content. XPS spectra analysis revealed that the cerium ions were reduced from Ce 4+ to Ce 3+ . The nonbonding to total oxygen ratio was estimated from the curve fitting of the O 1s core level spectra. Density and elastic parameters showed a nonlineal tendency in the change of the physical properties as a function of Na 2 O content. Finally, photoluminescence spectroscopy confirmed the presence of Ce 3+ ions. The characteristic 4f → 5d electronic transitions at 360 nm were detected, when a 280 nm excitation line of pulsed laser was used as excitation source.