“…The oxygen molar volume ( OMV ) was calculated based on molar volume [ 38 ]: where n i and x i in equation (11) represent the fraction of the oxygen atoms in each element and the molar fraction of the oxides of the fabricated glasses, respectively. One of the significant parameters to study the compactness and the tightness of the oxide network of the prepared glasses is through calculating oxygen packing density ( OPD ) using equation (12) [ 39 , 40 ]: where O n represents the number of oxygen atoms in the glass system and it can be calculated as follows: …”