New High Temperature Infrared Transmitting Glasses

摘要

An investigation was made into the basic chemical and physical nature of the nonoxide chalcogenide glasses. The glasses are found to be covalently bonded solids in which the nature of the parent chalcogenide is largely preserved. Within a few percent, the densities are a linear function of the molecular weight calculated from the compositional formula. Molar refraction and refractive index can be estimated within a few percent from density, compositional formula, and the covalent radii of the constituent elements. The interatomic distances calculated from simple stretching vibrational frequencies are very close to the sum of the appropriate covalent radii. A study of the vapor over heated glasses of different compositions indicates the group VA elements (P, As, Sb) in ternary systems are only loosely held in the glass structure and are not bonded to the chalcogenides in the presence of group IVA (Si or Ge) elements. A radial distribution analysis of the intensity of scattered x-ray energy as a function of angle of incidence for Si-Te glasses indicates the presence of evenly spaced Te chains. Structural measurements so far have provided a qualitative understanding of the structural nature of all the chalcogenide glasses. (Author)