  In this investigation, force field-based molecular dynamics (MD) simulations
have been employed to generate detailed structural representations for a range
of amorphous quaternary CaO-MgO-Al2O3-SiO2 (CMAS) and ternary CaO-Al2O3-SiO2
(CAS) glasses. Comparison of the simulation results with select experimental
X-ray and neutron total scattering and literature data reveals that the
MD-generated structures have captured the key structural features of these CMAS
and CAS glasses. Based on the MD-generated structural representations, we have
developed two structural descriptors, specifically (i) average metal oxide
dissociation energy (AMODE) and (ii) average self-diffusion coefficient (ASDC)
of all the atoms at melting. Both structural descriptors are seen to more
accurately predict the relative glass reactivity than the commonly used degree
of depolymerization parameter, especially for the eight synthetic CAS glasses
that span a wide compositional range. Hence these descriptors hold great
promise for predicting CMAS and CAS glass reactivity in alkaline environments
from compositional information.
