Fragility by Elastic Incoherent Neutron Scattering

The present work furnishes an operative definition for the fragility degree by using elastic incoherent neutron scattering ~EINS!. Such a definition is based on the relation between viscosity, a macroscopic quantity, and the atomic mean-square displacement, which refers to a nanoscopic property. This procedure has been used to analyze a set of glass-forming systems and it allows to obtain a linear dependence of the fragility parameter M, obtained by EINS, on the fragility parameter m, obtained by viscosity measurements.