EFFECT OF ALKALI FLUORIDE ON THE SHORT-RANGE STRUCTURES OF ZRF4-BAF2-BASED GLASSES

The short-range structures of ZrF4-BaF2-based glasses with added NaF or LiF are studied by XAFS. Their structures are compared with those of 66.7 ZrF4 . 33.3 BaF2 and 75 ZrF4 . 25 BaF2 glasses. Adding alkali fluoride the distance and coordination number of near neighbors around Zr decrease slightly and the coordination number about Ba is also less than that in binary ZrF4-BaF2 glasses. The mean distance between Zr and Zr suggests that there are F polyhedra around Zr linked by sharing the edges in the studied glasses. The intensities of the white lines in BaL(III) edges of these glasses are all less than in the case of BaF2. They reduce much greater in glasses with added NaF or LiF.