Structural analysis of 30O-30Al(2)O(3)-40B(2)O(3) (R = Mg, Ca or Sr) glasses

Bond-compression and ring-deformation models are used to quantitatively analyze the acoustical properties ( elastic moduli, Poisson's ratio, Debye temperature and longitudinal attenuation) of 30RO-30Al(2)O(3)-40B(2)O(3) glasses (in wt\%), where R = Mg, Ca or Sr. The network structure of the glass is quantified in terms of the four-fold coordinated formers, atomic ring size, cross-link density, first-order stretching force constant and bulk modulus. It is found that network strength increases in the order Mg > Ca > Sr. Structural changes of the glasses are deduced by relating the elastic moduli, the ratio of bond compression to experimental bulk modulus and ultrasonic attenuation to structural parameters and oxygen density.