Mechanical and thermodynamic properties of infrared transparent low melting chalcogenide glass

The properties of infrared (IR) transparent chalcogenide glass Se₅₇I₂₀As₁₈Te₃Sb₂ have been studied for the first time by dynamic mechanical analysis (DMA). This glass demonstrates both high transparency in a broad IR band (1-12 μm) and a particularly low softening point (near 50 °C). It is known as one of the best adhesives intended for the binding of IR optics elements. The DMA method gives valuable information about the complex Young's modulus of the glass in its softening region. In parallel with the study of mechanical properties of the glass the character of its glass transition process has been investigated. Our results of DMA were then compared with our thermodynamic data obtained by scanning calorimetry. The peak of mechanical losses in DMA appears to be situated considerably higher than the calorimetrically determined glass transition temperature.