A MEDIUM-RANGE STRUCTURAL PARAMETER OF OXIDE GLASSES BASED ON THERMAL-EXPANSION COEFFICIENT

Structural parameter M-p based on the principle of madelung constant o f ionic crystal was proposed to predict the medium-range structures of glasses using thermal expansion coefficients of them. The applicabili ty of M-p was investigated with M-p-structure relationships of four ki nds of typical oxide glasses: silicate, berate, phosphate and germanat e. Consequently, the composition dependence of the glass structures, e specially the basic unit polymerization, was exhibited well with M-p. It was evident that M-p was available as the medium-range structural p arameter. The structure of antimonate glasses was presumed with M-p th at it was not simple three-dimensional network and there was little ch ange of the polymerization degree with network modifier content. Then, it was suggested that, in the case of an investigation of the glass s tructure, the structural parameter M-p makes possible to predict the c omposition dependence of medium-range structure, particularly the poly merization degree change.