Provided is a novel glass filler having a low permittivity. The glass filler provided includes a glass composition, wherein the glass composition includes, in wt %:95≤SiO.sub.2≤99.5; 0≤B.sub.2O.sub.3≤2; 0.01≤Al.sub.2O.sub.3≤4; 0≤R.sub.2O≤4; 0.01≤RO ≤4; and 0≤TiO.sub.2≤4, where RO is at least one selected from MgO, CaO, SrO, and ZnO, and R.sub.2O is at least one selected from Li.sub.2O, Na.sub.2O, and K.sub.2O. This glass filler can have a permittivity of less than 4 at 1 GHz.

An optical fiber according to an embodiment includes a core, a cladding, and a coating layer. At the boundary between the core and the cladding, the local sound velocity decreases in the direction from the core side toward the cladding side. At least in the cladding, the local sound velocity changes continuously in a radial direction. Further, the line width of the Brillouin gain of the light beam guided by the fundamental mode is 60 MHz or more.

Provided is a titanium-containing quartz glass having excellent UV absorption. The quartz glass absorbs ultraviolet rays having a wavelength of 250 nm or less, ozone generation-related adverse effects on the human body, are prevented, a decrease in transmittance of the quartz glass in the range from near-ultraviolet to visible light due to being colored when irradiated with ultraviolet rays does not occur, absorption build-up or lamp burst-inducing deformation build-up, which is caused by a structural change in the quartz glass that occurs in the range of 200-300 nm when irradiated with ultraviolet rays, is suppressed, and a decrease in transmittance at intended wavelength ranges does not occur even when exposed to ultraviolet rays. The titanium-containing quartz glass having excellent UV absorption is colorless, wherein the average concentration of titanium is 10-500 ppm, the concentration of OH group is 10-350 ppm.

Doped quartz glass components for use in a plasma-assisted manufacturing process contain at least one dopant which is capable of reacting with fluorine to form a fluoride compound, and the fluoride compound has a boiling point higher than that of SiF.sub.4. The doped quartz glass component has high dry-etch resistance and low particle formation, and has uniform etch removal when used in a plasma-assisted manufacturing process. The doped quartz glass has a microhomogeneity defined by (a) a surface roughness with an R.sub.a value of less than 20 nm after the surface has been subjected to a dry-etching procedure as specified in the description, or (b) a dopant distribution with a lateral concentration profile in which maxima of the dopant concentration are at an average distance apart of less than 30 μm.

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 μm. 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.

An optical fiber according to an embodiment includes a core, a cladding, and a coating layer. At the boundary between the core and the cladding, the local sound velocity decreases in the direction from the core side toward the cladding side. At least in the cladding, the local sound velocity changes continuously in a radial direction. Further, the line width of the Brillouin gain of the light beam guided by the fundamental mode is 60 MHz or more.

A chalcopyrite compound-based thin film in which an alkali metal is incorporated, and a method of fabricating the same are provided. The chalcopyrite compound-based thin film in which an alkali metal is incorporated may have improved film characteristics such as excellent chalcopyrite crystal characteristics and improved surface characteristics, and may exhibit improved optical characteristics by control of the distribution of constituent elements in the chalcopyrite compound layer. Accordingly, performance of a solar cell including the chalcopyrite compound-based thin film may be improved. The chalcopyrite compound-based thin film may be easily fabricated through a solution process.

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.

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.

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.