ALKALINE-EARTH GALLOGERMANATE GLASSES

This chapter discusses the formation, structure, and properties of alkaline earth gallogermanate glasses. Specific attention is focused on the barium gallogermanate family of glasses because of their optical properties which make them excellent candidates for infrared optical applications. The structural model for these lasses is reviewed and recent supporting evidence from infrared and Raman spectral studies and X-ray absorption studies is presented. Optical and physical properties including infrared transparency, Rayleigh scattering, and refractive index, density/molar volume, glass transition temperatures, viscosity, thermal expansion, and durability are presented and discussed in terms of the structure of the glass. Throughout this chapter, the structure and properties of the alkaline earth gallogermanate glasses are compared and contrasted to other similar glass systems including alkali, germanate, alkaline earth germanate, alkali gallogermanate, and alkaline earth aluminogermante, glasses.