The Red‐Shift of Ultraviolet Spectra and the Relation to Optical Basicity of Ce‐Doped Alkali Rare‐Earth Phosphate Glasses

The ultraviolet absorption and emission spectra of Ce 3+ doped phosphate glasses based on gadolinium and sodium phosphates are studied in the present work. Compared with the cerium‐free phosphate glass matrixes, CePO 4 doping shifts the ultraviolet absorption edge of glasses into the longer wavelength because of the 4f–5d absorption transition of Ce 3+ . The emission spectra correlate such red‐shift with glass compositions. Explanations are based on variation in the optical basicity of glasses, which corresponds not only to the alkali content but also to the O/P ratio. The latter is proportional to the number of nonbridging oxygen in the oxyanion unit (PO 4 ), and most likely plays an overwhelming role in the overall optical basicity of glasses.