Direct evidence of rigidity loss and self-organization in silicate glasses

The Brillouin elastic free energy change ΔΦ between thermally annealed and quenched (Na2O)x(SiO2)1−x glasses is found to increase linearly for x>0.23 (floppy phase), and to nearly vanish at x 0.23, but to nearly vanish in the 0.18<x<0.23 range, suggesting the existence of an intermediate phase between the floppy and stressed-rigid phases.