Mixed oxidation states of Yb and Sm in Si-Al-O-N glasses

The mechanical and optical properties of samarium and ytterbium doped Y-Si-Al-O-N glasses have been studied. It has been shown that both samarium and ytterbium undergo a reduction from the trivalent state in the raw materials to the divalent state in the glass, the degree of conversion depending on the melting time. Emission spectra of samarium containing glasses show the presence of both Sm3+ as well as that of Sm2+, which is also reflected by the Young's modulus and density. A broad absorption band of Yb2+ characterizes the reflection spectra of ytterbium containing glasses, indicating a similar reduction, while a second absorption band suggests the presence of some remnant Yb3+. The other properties of these glasses also appear to confirm a mixed oxidation state of Yb. These reductions have been attributed to the reducing power of chemically incorporated nitrogen (N3−) in the glass matrix, as demonstrated earlier for Eu-Si-Al-O-N glasses.