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The density, surface tension and viscosity of the 50RO–50P2O5 (R: Mg, Ca, Sr, Ba and Zn) glass melts have been measured over the range, 1073–1623 K. The effects of R cations on these properties have been investigated. The density of the melt was found to increase in the order, R: Mg Ca Zn Sr Ba, with increasing molar weight of cation. The surface tension in the temperature range of 1373–1473 K increased approximately with cation in the order, R: Zn Ba Mg Ca Sr. The viscosity and the negative, temperature coefficient of surface tension increased in the order, R: Ba Sr Ca Zn Mg. All melts exhibited negative temperature coefficients of surface tension. The effect of Mg and Zn cations on the properties were different to that for Ba, Sr, and Ca cations and this is discussed using bulk glass data published in a previous report. The features of Mg and Zn metaphosphate glass melts, that is high values of viscosity, and temperature coefficient of surface tension, are related to the small Oxygen Coordination Number of the cations (=4) when compared with those of Ca, Sr, Ba metaphosphate glass melts.

Refractive indexes of oxide glasses: silica, borate, silicate, aluminate, germanate, tellurite, antimonate and heavy metal gallate are measured in the wavelength range of 0.40–5.03 μm. The zero material dispersion wavelength (ZMDW) was determined using the refractive index data. To predict the ZMDW, we calculated the molecular electronic polarizability, α i , of oxide glasses using the Lorentz-Lorenz equation. An empirical equation between ZMDW and α i was obtained, from which the ZMDW from the compositional parameter, α i can be calculated.

Refractive index dispersion curves in the wavelength region of 0.40 to 5.03 μm are presented for multi-component oxide glass systems: borate, silicate, aluminate, germanate, tellurite, antimonate and heavy metal gallate. The material dispersion was determined using the refractive index data. Reflection spectra in the ultraviolet and infrared regions were measured to investigate the effects of electronic transitions and lattice vibrations on the material dispersion. Thallium tellurite, thallium antimonate and lead gallate glasses exhibit zero material dispersion wavelengths (ZMDWs) over 2.4 μm. The factors affecting the ZMDW are discussed.