The structure and properties of xZnO-(67-x)SnO-33P2O5 glasses: (III) Photoelastic behavior

The effects of composition and structure on stress-induced birefringence were studied for glasses with the nominal molar compositions xZnO-(67-x)SnO-33P2O5. The photoelastic constant (PEC) changes systematically from negative values to positive values when ZnO replaces SnO, and PEC ≈ 0 when x = 18.5 mol%. The zero PEC composition can be predicted from the observed coordination numbers and bond lengths of the Zn-, Sn-, and P-polyhedra using an empirical model from the literature.