Glass‐Forming Systems Involving GeO 2 with Bi 2 O 3 , Ti 2 O, and PbO

The previously studied system GeO 2 ‐Bi 2 O 3 ‐TI 2 O was extended with the addition of PbO using air‐ and water‐quenched melted samples. Large areas of glass formation were found in the systems GeO 2 –Bi 2 O 3 –PbO and GeO 2 –PbO–Tl 2 O at all but the lowest GeO 2 contents. Glasses were examined by powder X‐ray diffraction, differential thermal analysis, thermomechanical analysis, and Archimedes’technique to obtain glass transition and crystallization exotherm temperatures, thermal expansion coefficients, and densities, which are presented in diagrams for the GeO 2 ‐PbO binary and for the two ternary systems. Based on calculated values of λ 0 , the wavelength for zero material dispersion, compositions in this system may be useful for construction of ultralow‐loss optical waveguides in the μm region.