Compositional influence on shape and position of the first sharp diffraction peak (FSDP) in silicate and germanate glasses

Silicate and germanate glasses studied by X-Ray diffraction methods (WAXS) show characteristic features concerning the first peak of their scattering functions (FSDP : first sharp diffraction peak). Shapes and positions of the FSDPs develop systematically with composition. The shape of the FSDPs can only be described by introducing up to three peaks. We assume that the glass networks are heterogeneous in the scale of medium range order with respect to their chemistry and/or topology and these regions are mainly connected coherently.