OPTICAL PROPERTIES VERSUS STRUCTURAL PACKING DENSITY FOR Na2O-Al2O3-B2O3 GLASSES

Six glasses belonging to the Na2O-Al2O3-B2O3 oxide system with the molar composition (35-x)Na2O center dot xAl(2)O(3)center dot 65B(2)O(3) were synthesized. Refractive index, n, and density, d, were measured on these glasses; the experimental values were used to compute a series of optical properties: transmission, T, molar refractivity, R-m, mass refractivity, R-M, and specific refractivity, r. Correlations between optical properties and chemical composition, glass features at the first structural level (molar volume, V-m) and compactness, C, were drawn. It was concluded that glass compactness (a feature describing the atomic level - sub-nanoscale) is an influential parameter on optical properties of the glasses, which manifest on a macroscopic scale.