Physical Properties and Structure of Silica‐Alumina‐Europium Oxide Glasses

SiO 2 –Al 2 O3–Eu 2 O 3 glasses were prepared for the composition 50siO 2 ·(50 – x )Al 2 O 3·x Eu 2 O 3 , and their density, sound velocity, and elastic modulus were measured. The chemical shift of the AIK a band emission spectra and the isomer shift of 151 Eu by Mössbauer effect were obtained to determine the coordination states of Al 3+ and Eu 3+ ions in these glasses. It was found that the coordination number of Eu 3+ ions was 12 and that the average coordination number of A1 3+ ions was almost 5 in these glasses. By introducing Eu 2 O 3 , the packing of constituent ions was strongly enhanced and the elastic modulus increased in this system. The compositional dependence of the molar volume and elastic modulus were explained by these states of high coordination number for Eu 3+ and low coordination number for Al 3+ ions compared with those in the corresponding M 2 O 3 crystals.