The optical properties and structural relationships of ternary meta- and pyro-phosphate glasses are found to be correlated with electronic polarizability. In particular, the optical properties of photoelasticity and refractivity have similar tendencies with electronic polarization evolution, which can be estimated from the Lorentz–Lorenz equation and the compositional data of reported electronic polarizability with small corrections with structural viewpoint. Combinations of the oxide constituents of BaO, SnO, and ZnO result in systematic changes of optical properties, which can be attributed to the phosphate-anion network revealed by 31P magic-angle spinning nuclear magnetic resonance spectroscopy. The small photoelastic constants are obtained with the ubiquitous high polarizable cation of Ba2+ and the substitution of Sn2+ with Zn2+ in the ternary phosphate glasses.