Abstract: Provided are a process for the production of a precision press-molded article having a high transmittance and a method of treating a glass to color or decolor the glass, the process comprising heat-treating a press-molded article containing at least one selected from WO3, Nb2O5 or TiO2 in an oxidizing atmosphere to produce a glass molded article, and the method comprising heat-treating a colored glass containing at least one oxide of WO3 and Nb2O5 in an oxidizing atmosphere to decolor the glass, or heat-treating a glass containing at least one oxide selected from WO3, Nb2O5 or TiO2 in a non-oxidizing atmosphere to color the glass.

Abstract: Provided are a process for the production of a precision press-molded article having a high transmittance and a method of treating a glass to color or decolor the glass, the process comprising heat-treating a press-molded article containing at least one selected from WO3, Nb2O5 or TiO2 in an oxidizing atmosphere to produce a glass molded article, and the method comprising heat-treating a colored glass containing at least one oxide of WO3 and Nb2O5 in an oxidizing atmosphere to decolor the glass, or heat-treating a glass containing at least one oxide selected from WO3, Nb2O5 or TiO2 in a non-oxidizing atmosphere to color the glass.

Abstract: An optical glass having a high refractive index and high dispersion characteristics that is suited to application to precision press molding to precisely mold the shape of final products for objectives not requiring grinding or polishing. An optical glass exhibiting a refractive index in the range of from 1.75 to 2.0, an Abbé number in the range of from 20 to 28.5. Optical parts comprised of this glass; press-molding materials comprised of this glass; methods of manufacturing the same; and methods of manufacturing molded glass products employing these materials.

Abstract: A method for manufacturing a glass fiber includes a process of drawing a starting glass material partially or entirely made of chalcogenide glass or oxychalcogenide glass, such as preform rod, rod-in-tube, or jacketing tube, into a glass fiber in an atmosphere containing sulfur. The concentration of the sulfur in the atmosphere is set at sulfur's vapor pressure or greater around the glass surface at a maximum temperature of the glass fiber while the glass fiber is drawn, thereby fabricating the glass fiber without forming substantially any crystallization on the glass surface.

Abstract: Disclosed are laser glasses composed of a Ga--Na--S glasses doped with one or more kinds of activating ions, laser glass fibers comprising a core and a clad wherein the core is composed of the above-mentioned laser glasses of the present invention and optical fiber amplifiers comprising a pumping source, a laser glass fiber and a means for introducing pumping light and signal light into the laser glass fiber wherein the laser glass fiber is the above-mentioned laser glass fiber of the present invention. The laser glasses of the present invention show high radiative quantum efficiency and host glass stability and can be produced easily.