Figure 5: Exploring the M/H extremum via the dual-defect framework computed from atomistic simulations.

(a) C/S-λ(Si-O) and (b) C/S-λ’(Cw-O). Both contour plots show a region in which M/H is maximized. The correlation among defect attributes (c) C/S-λ(Si-O) and (d) λ’(Cw-O), and their (c) linear and (d) piecewise linear fit to the simulation results, which correlate with highest values of M/H described by packing of silica chains (responsible for higher stiffness) and openness of Cw-O network (responsible for lower hardness). The arrows in (c) and (d) indicate that the samples at Ca/Si~1.5 with high M/H would have lowest Si-O and highest Cw-O medium-range correlation lengths.