An optical fiber in which the increase of attenuation can be reduced is offered. An optical fiber is made of silica glass and includes a core and a cladding enclosing the core. The refractive index of the cladding is smaller than that of the core. The core includes chlorine and any of the alkali metal group. The chlorine concentration is 1 ppm or more in the whole region of the core. In the whole region of the core, the absolute value of rate of radial change of the chlorine concentration is smaller than 2000 ppm/m.

The present invention provides a composite shaped body comprising silica nanoparticles and an organic polymer, wherein the silica nanoparticles and the organic polymer form a three-dimensional network; thereby provides: a composite shaped body which exhibits excellent formability and fabricability and which is also suited for use, for example, in producing a silica glass provided with an electrical conductivity; and a silica glass (especially, an electrically conductive silica glass) obtained by firing the composite shaped body.

A method for forming high purity silica articles. The high purity silica articles can be particularly suitable for forming packaging such as packaging for pharmaceutical applications. The method for forming high purity silica articles can comprise, in one embodiment, (a) forming a fused quartz melt from a SiO.sub.2 raw material; (b) forming a quartz tube from the fused quartz melt; (c) treating the quartz tube with an acid composition; (d) heat treating the quartz tube subsequent to treating with the acid composition; and (e) optionally treating the quartz article with an acid composition subsequent to the heat treating operation. The method can enhance the purity of silica glass articles and products made therefrom.

A resin composition for inorganic molded article production use, which is provided with inorganic particles each containing amorphous SiO.sub.2 and a photocurable resin composition, in which the photocurable resin composition contains a photocurable resin precursor and a photopolymerization initiator, the content of the inorganic particles is 60% by mass or more with respect to the total amount of the photocurable resin composition and the inorganic particles and is 60% by mass or more with respect to the entire amount of the resin composition for inorganic molded article production use, and the viscosity of the composition for inorganic molded article production use is 10000 mPa.Math.s or less.

A discharge lamp includes a discharge vessel. A xenon gas is sealed within the discharge vessel so as to serve as a light emitting gas, the discharge vessel is made from quartz glass, a pair of electrodes are arranged so as to face each other in the discharge vessel, and the discharge vessel has a chip portion. The chip portion is made from a glass member that has a composition different from that of the discharge vessel, and the glass member has a transmittance of 50% or more over a wavelength range from 170 nm to 300 nm.

A method is provided for producing a glass ceramic element with a patterned coating is provided. The method includes: providing a glass ceramic element with a coating which is at least partially light-blocking and preferably opaque in the visible spectral range; irradiating the glass ceramic element with a pulsed laser beam on the face provided with the coating so that the coating is removed by ablation; during irradiating the laser beam is directed over the surface of the glass ceramic element so that a portion of the coating is removed which has a greater lateral extent than the diameter of the laser beam; and once the coating has been removed, irradiating the glass ceramic with the laser in the region where the coating has been removed, thereby optically modifying the glass ceramic in the irradiated region.

A discharge lamp includes a discharge vessel. A xenon gas is sealed within the discharge vessel so as to serve as a light emitting gas, the discharge vessel is made from quartz glass, a pair of electrodes are arranged so as to face each other in the discharge vessel, and the discharge vessel has a chip portion. The chip portion is made from a glass member that has a composition different from that of the discharge vessel, and the glass member has a transmittance of 50% or more over a wavelength range from 170 nm to 300 nm.

A color-stable, antimicrobial glass powder obtained by partial ion exchange at a temperature of 300 C. to 350 C. and an exchange time of 1 to 120 minutes, is formed of a mixture of porous glass particles having micropores and macropores made of borosilicate glass continuously foamed by extrusion having a Fe.sub.2O.sub.3 content <0.2 wt %, in which the obtained glass foam is subsequently comminuted by dry grinding to average particle sizes of 1.0 to 8.0 m. The mixture includes color stabilizers containing 0.1% to 0.2% of ammonium ions and antimicrobial metal ions from dissolved metal salts, wherein the metal ions may be silver and/or zinc and/or copper ions. A method for the production of a color-stable, antimicrobial glass powder and applications for using the color-stable, antimicrobial glass powder are also provided.

A low cost method for producing a mechanically and thermally stable composite body containing a first layer of a material with a high silicic acid content and an additional component connected to a second layer of a material with a high silicic acid content and an additional component in a second concentration differing from the first concentration is provided. The method involves (a) preparing a first slurry layer having a free surface using a first shirt mass containing SiO.sub.2 particles and an additional component dispersed in a first dispersing agent, (b) providing a second slurry mass containing SiO.sub.2 particles and an additional component in a second concentration dispersed in a second dispersing agent, (c) forming a composite-body intermediate product by applying the second slurry mass to the free surface of the first slurry layer, and (d) heating the composite-body intermediate product while forming the composite body.

A method of forming a doped silica-titania glass is provided. The method includes blending batch materials comprising silica, titania, and at least one dopant. The method also includes heating the batch materials to form a glass melt. The method further includes consolidating the glass melt to form a glass article, and annealing the glass article.