Tellurite glasses containing silver and vanadium oxides: quantitative analysis of elastic moduli

Ring deformation and bond compression models are used to analyze quantitatively room temperature elastic moduli of x(1)Ag(2)O-x(2)V(2)O(5)-(1-x(1)-x(2))TeO(2) glass systems, where 3.7 <= x(1)<= 19.4 mol\% and 24.7 <= x(2)<= 42.7 mol\%. The main parameters in the analysis are estimated atomic ring size, average crosslink density, first order stretching force constant and theoretical bond compression bulk modulus K(bc). Structural changes are deduced by relating the ratio K(bc)/K(e) to both molar volume and atomic ring size of glasses. It is found that increasing the Ag(2)O concentration opens the glass structure by breaking V-O-Te linkages and creating nonbridging oxygen atoms (NBOs) according to the reaction: Ag(2)O + Te-(eq)O(ax)-V -> Te-(eq)O(-)Ag(+) (or Te-(ax)O(-)Ag(+)) + V-O(-)Ag(+). In addition, Ag(2)O-V(2)O(5)-TeO(2) glasses have a relatively closed (small rings) structure when compared to.Ag(2)O-B(2)O(3)-TeO(2), B(2)O(3)-SiO(2), Na(2)O-B(2)O(3)-SiO(2) or Na(2)O-K(2)O-CaO-PbO-SiO(2) glasses.