Tellurite Glasses

The boundaries of regions of glass‐forming compositions were determined in binary tellurite systems with alkali, alkaline‐earth, and heavy‐metal oxides, and in the ternary systems TeO 2 ‐WO 3 ‐Ta 2 O 5 , TeO 2 ‐WO 3 ‐BaO, TeO 2 ‐WO 3 ‐Bi 2 O 3 , and TeO 2 ‐WO 3 ‐Tl 2 O. On the basis of a structural interpretation of liquid immiscibility in binary oxide systems and of X‐ray diffraction investigation of the structure of tellurite glasses, a crystallochemical interpretation of glass formation is proposed, as well as a method for calculating the modifier‐poor boundaries of the regions of glass‐forming compositions in binary systems. An investigation of the crystallizability, density, optical constants, spectral transmission characteristics, and chemical durability of the tellurite glasses as functions of their chemical compositions has led to the development of a new flint‐type optical glass, with n d = 2.1608 and v = 17.4, possessing a high chemical durability and resistance to devitrification.