Empirical methods for estimating the linear coefficient of expansion of oxide glasses from their composition

Empirical methods for estimating the linear coefficient of expansion (α) of oxide glasses have been derived. New parameters (β_i) are define for the glass modifiers. The β_i are calculated from the ionic radius R, charge Z, and the electronegativity EN of the modifiers. β_i parameters and their normalized values (γ_i) with respect to a standard modifier, classify the modifiers according to their contribution to the thermal expansion. Two semi-emperical relations were derived for the calculation of α. Calculated expansion coefficient for over 500 glass compositions are within ± 15% of the measured values. The application of the methods to ternary, quaternary and multicomponent industrial glasses is treated.