OPTICAL AND THERMAL-PROPERTIES OF SOME CHEMICALLY DURABLE LEAD PHOSPHATE-GLASSES

This paper describes the ultraviolet, visible, infrared, chemical and thermal properties of the recently developed lead phosphate based glas ses The optical properties of some glasses are studied by measuring th eir refractive index, ultraviolet-visible absorption and infrared tran smittance; the thermal properties by differential thermal analysis and thermal mechanical analysis and the chemical durabilities by determin ing the dissolution rates of the glasses in both acidic and basic aque ous solutions at 90 degrees C for 14 days or more. The origins of low absorption in the visible region of the spectrum and transmission into the mid-infrared are discussed as well as a desirable combination of good chemical durability and high thermal expansion coefficient. The g lasses are expected to be useful for a variety of applications includi ng hermetic seal to high expansion metals visible and infrared optical components.