Fragility percentage evaluation for glass forming melts

The dependence of the viscosity on temperature for glass forming melts separates them into two categories: fragile and strong. We propose an intuitive method for quantitative evaluation of the glass forming melts fragility by a structural parameter - fragility percentage pF which allows the comparison of the glass melts without considering their particular chemical composition. A strong correlation between fragility percentage and the main number of non-bridged oxygen (O nb ) was established. The study is also related to a numerical application of the proposed indicator made for glass with different chemical compositions compared with the base oxide system Na 2 O-SiO 2. The greater the basicity of the glasses the more fragile character of the glass forming melts is observed.