Abstract
Heavy metal oxide glasses with and without minor additions of Silica and Germania in the system PbO-Bi2O3-Ga2O3 have been prepared which have potential applications for infrared fibres. Viscosity measurements using penetration viscometry were first carried out on sample of glass No. 711 provided by National Bureau of Standards (NBS) over a range of 107 to 1010 Pa.s and is in accordance with NBS data having mean error of 1.35% using modified-Nemilov equation. The viscosity of glasses studied fell sharply about three orders o of magnitude in a temperature interval of less than 45 C. The results are discussed in relation to activation energy for viscous flow and also fragility of the melts is compared.
Keyword(s)
Metal oxide glass, infrared fibre, viscometry, activation energy