Abstract: 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.

Abstract: One aspect is a reflective member, which has a laminated structure in which transparent quartz glass members are formed on an upper surface and a lower surface of an opaque siliceous sintered powder layer. The opaque siliceous sintered powder layer has a thickness of 0.1 mm or more and a thickness distribution of ±0.05 mm or less. When a load is applied to each of the transparent quartz glass members on an upper surface and a lower surface of the laminated structure in a direction parallel to the laminated structure, the reflective member is fractured at a load of 5 N or more per square centimeter. The laminated structure includes a semi-transparent portion having a width of 0.01 mm or less, which has an intermediate opacity between an opacity of the opaque siliceous sintered powder layer and an opacity of each of the transparent quartz glass members.

Abstract: Described is a process for the production of synthetic fused silica in which the deposition surface is located for a period of at least 50% of the build-up time of the soot body at a burner distance in which the horizontally integrated luminous intensity of the flame of the burner used in the targetless state is still at least ? of the maximum horizontally integrated luminous intensity of the flame.

Abstract: A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. The displacement of the shear zone along the longitudinal axis of the blank is superimposed by a simultaneous oscillating motion of the shear zone along the longitudinal axis of the blank. The first end of the blank is rotated at a first rotational speed and the second end of the blank is rotated at a second rotational speed. An oscillating motion of the shear zone is generated by periodically varying the first and/or second rotational speed.

Abstract: Provided is a heat reflective member, which is prevented from braking even in a high-temperature environment. It generates no dust in use, and can be washed with a chemical liquid. The heat reflective member has a laminated structure in which quartz glass layers are formed on an upper surface and a lower surface of a siliceous sintered powder layer. The heat reflective member includes: an impermeable layer which is formed at a portion of the siliceous sintered powder layer at an end portion of the heat reflective member, which has a thickness at least larger than half of a thickness of the siliceous sintered powder layer, and through which a gas or a liquid is prevented from penetrating; and a buffer layer which is formed between the impermeable layer and the siliceous sintered powder layer, and which changes in density from the impermeable layer toward the sintered powder layer.

Abstract: A method for determining an index-of-refraction profile of an optical object, which has a cylindrical surface and a cylinder longitudinal axis, said method comprising the following method steps: (a) scanning the cylindrical surface of the object at a plurality of scanning locations by means of optical beams; (b) capturing, by means of an optical detector, a location-dependent intensity distribution of the optical beams deflected in the optical object; (c) determining the angles of deflection of the zero-order beams for each scanning location from the captured intensity distribution, comprising eliminating beam intensities, and (d) calculating the index-of-refraction profile of the object on the basis of the angle-of-deflection distribution, wherein method steps (a) and (b) are carried out with light beams having at least two different wavelengths.

Abstract: Described is a method of producing synthetic fused silica in which the synthetic flame used in the method has a ratio of the Full Width at Half Maximum (FWHMvert) vertical luminous intensity to the Full Width at Half Maximum (FWHMhori) horizontal luminous intensity greater than 10 in a targetless state, the luminous intensities being measured in candela/mm2.

Abstract: A process for the production of a fluorinated quartz glass including the steps of generating SiO2 particles in a synthesis burner; depositing the resulting SiO2 particles into a body; and vitrifying the resulting body, wherein a fluorinating agent having a boiling point greater than or equal to ?10° C. is supplied to the synthesis burner.

Abstract: A quartz glass body and a process for the preparation of a quartz glass body is disclosed. One process includes providing a silicon dioxide granulate from a pyrogenic silicon dioxide powder, making a glass melt out of the silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. In at least one process a silicon component different from silicon dioxide is added. A quartz glass body is obtainable by this process. A light guide, an illuminant and a formed body, are each obtainable by further processing of the quartz glass body.

Abstract: In a method of manufacturing a tube of quartz glass by molding a hollow cylinder having a wall thickness of at least 20 mm, the cylinder is continuously fed under rotation about a rotational axis into a heating zone at a relative feed rate VC, softened and radially expanded under the effect of a gas pressure. A tube strand is continuously formed and is withdrawn at a withdrawal rate VT. In order to mold thick-walled initial hollow cylinders of quartz glass into tubes with larger diameter, the gas pressure is used as an actuating variable of a diameter regulation for the tube outer diameter or for a geometrical correlated parameter thereof, and in a pressure build-up phase the gas pressure is gradually increased from a lower initial value to a higher final value, and that the following applies to the ratio of VC and VT:VT=VC±0.2·VC.

Abstract: A process for producing a fluorinated quartz glass is described, including providing an SiO2 soot body; reacting the SiO2 soot body with a fluorinating agent having a boiling point of greater than or equal to ?10° C. to obtain a fluorinated SiO2 soot body; and vitrifying the fluorinated SiO2 soot body.

Abstract: Described is a process for the refinement of a quartz powder, comprising the step of separating microparticles of refractory minerals, in particular minerals containing rare earth metal compounds, from the quartz powder by an elutriation step.

Abstract: One aspect is a method for producing a multilayered silica glass body. The method involves producing a multilayered silica glass body in which a transparent silica glass layer is provided on the surface of a siliceous substrate made of a siliceous material. The method includes preparing the siliceous substrate, preparing a silica slurry in which silica particles are dispersed in a liquid, applying the silica slurry to the surface of the siliceous substrate, leveling the silica slurry applied to the surface of the siliceous substrate by applying vibration to the siliceous substrate, drying the leveled silica slurry, and vitrifying the dried silica slurry by heating to form a transparent silica glass layer. As a result, a transparent silica glass layer of uniform thickness is obtained at excellent yield, and a method for producing a multilayered silica glass body easily in a short time is provided.

Abstract: One aspect relates to a process for the preparation of a quartz glass body, including providing a silicon dioxide granulate, wherein the silicon dioxide granulate was made from pyrogenic silicon dioxide powder and the silicon dioxide granulate has a BET surface area in a range from 20 to 40 m2/g, making a glass melt out of silicon dioxide granulate in an oven and making a quartz glass body out of at least part of the glass melt. The oven has at least a first and a further chamber connected to one another via a passage. The temperature in the first chamber is lower than the temperature in the further chambers. On aspect relates to a quartz glass body which is obtainable by this process. One aspect relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

Abstract: In a known method for treating pourable, inorganic grain, a heated rotary tube is used that rotates about an axis of rotation and surrounds a treatment chamber that is divided into a plurality of treatment zones by means of separating elements. The grain is supplied to the treatment chamber at a grain inlet side and is transported, in a grain transport direction, to a grain outlet side and is exposed to a treatment gas in the process. In order, proceeding herefrom, to allow for reliable and reproducible thermal treatment of pourable inorganic grain, in particular SiO2 grain in the rotary kiln, in a manner having low and effective consumption of treatment gas, it is proposed for spent treatment gas to be suctioned out of a reaction zone of the treatment chamber, by a gas manifold that rotates about the longitudinal axis thereof.

Abstract: A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. The displacement of the shear zone along the longitudinal axis of the blank is superimposed by a simultaneous oscillating motion of the shear zone along the longitudinal axis of the blank. The first end of the blank is rotated at a first rotational speed and the second end of the blank is rotated at a second rotational speed. An oscillating motion of the shear zone is generated by periodically varying the first and/or second rotational speed.

Abstract: Producing a molded body made of opaque quartz glass includes providing SiO2 grains obtained by comminuting quartz glass having a purity of at least 99.9 wt % SiO2, forming a slurry containing a suspension liquid and the SiO2 grains and which has a total solids content, wet grinding the SiO2 grains in the slurry so as to form ground SiO2 grain particles, forming a porous green body from the slurry, and sintering the porous green body. To provide a low cost quartz glass, the wet grinding of the SiO2 grains takes place at least temporarily in the presence of SiO2 nanoparticles, the proportion of which in the total solids content of the slurry is in the range of 0.1 wt % to 10 wt %, and the slurry has a solids content in the range of 76 to 80 wt % after addition of the SiO2 nanoparticles and after the wet grinding.

Abstract: Known heating burners for producing a welded joint between components of quartz glass include a burner head in which at least one burner nozzle is formed, a burner-head cooling system for the temperature control of the burner head and a supply line connected to the burner nozzle for a fuel gas. Starting from this, to modify a heating burner in such a way that impurities in the weld seam between quartz-glass components to be connected are largely avoided, it is suggested that the burner head should include a base body of silver or of a silver-based alloy.

Abstract: In known methods for producing a glass component, a void-containing intermediate product containing doped or non-doped SiO2 is inserted into a sheath tube composed of glass, which has a longitudinal axis and an inner bore, and is thermally treated therein. In order to subject the intermediate product to a thermal and/or reactive treatment that is reproducible and uniform in its effect from this starting point, it is proposed in one embodiment that into the sheath tube's inner bore a first gas-permeable gas diffuser is inserted which is displaceable along the sheath tube's longitudinal axis and is pressed against the intermediate product during the thermal treatment.

Abstract: One aspect relates to a process for the preparation of a quartz glass body including, providing a silicon dioxide granulate obtainable from a silicon dioxide powder, wherein the silicon dioxide granulate has a larger particle size than the silicon dioxide powder, making a 5 glass melt out of silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. The melting crucible has at least one inlet and at least one outlet. A least part of the glass melt is removed via the melting crucible outlet. One aspect further relates to a quartz glass body which is obtainable by this process. One aspect further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing 10 of the quartz glass body.