A method for producing a solid body of glass is described. The method comprises providing a polymerisable composition, curing the polymerisable composition to obtain a cured body, subjecting the cured body to thermal debinding to substantially remove the organic components in the cured body, and subjecting the cured body to sintering to obtain a solid body of silica glass. The polymerisable composition one or more at least partially organic polymerisable compound(s) which form a liquid composition at operating temperature and a solid source of silica as colloidal silica particles or silica glass micro-/nanoparticles dispersed in the liquid composition. The one or more at least partially organic polymerisable compounds comprises at least one organosilicon compound as a second source of silica that is liquid or solubilisable in the liquid composition at operating temperature to thereby increase the silica loading of the cured body prior to sintering. Compositions and methods for producing solid glass objects by additive manufacturing are also described.

A method for producing a solid body of glass is described. The method comprises providing a polymerisable composition, curing the polymerisable composition to obtain a cured body, subjecting the cured body to thermal debinding to substantially remove the organic components in the cured body, and subjecting the cured body to sintering to obtain a solid body of silica glass. The polymerisable composition one or more at least partially organic polymerisable compound(s) which form a liquid composition at operating temperature and a solid source of silica as colloidal silica particles or silica glass micro-/nanoparticles dispersed in the liquid composition. The one or more at least partially organic polymerisable compounds comprises at least one organosilicon compound as a second source of silica that is liquid or solubilisable in the liquid composition at operating temperature to thereby increase the silica loading of the cured body prior to sintering. Compositions and methods for producing solid glass objects by additive manufacturing are also described.

A quartz glass crucible including bottom, curved, and straight body portions, where the quartz glass crucible includes an outer layer including opaque quartz glass containing bubbles, and an inner layer including transparent quartz glass, the outer layer fabricated from different types of raw material powder, the outer layer having regions sectioned by bubble content densities, and bubble content densities of two outer layer adjacent regions, when d.sub.a (pcs/mm.sup.3) is defined as content density of a region “a” having a greater content density, and d.sub.b (pcs/mm.sup.3) is defined as content density of a region “b” having a smaller content density, a difference D=(d.sub.a−d.sub.b)/d.sub.b between content densities of the two regions is 10% or more.

A quartz glass crucible including bottom, curved, and straight body portions, where the quartz glass crucible includes an outer layer including opaque quartz glass containing bubbles, and an inner layer including transparent quartz glass, the outer layer fabricated from different types of raw material powder, the outer layer having regions sectioned by bubble content densities, and bubble content densities of two outer layer adjacent regions, when d.sub.a (pcs/mm.sup.3) is defined as content density of a region “a” having a greater content density, and d.sub.b (pcs/mm.sup.3) is defined as content density of a region “b” having a smaller content density, a difference D=(d.sub.a−d.sub.b)/d.sub.b between content densities of the two regions is 10% or more.

A fused quartz crucible for pulling a single crystal of silicon by the Czochralski technique, has an inner side with an inner layer of fused quartz that forms a surface, the inner layer being provided with a crystallization promoter which on heating of the fused quartz crucible during use, in crystal pulling, causes crystallization of fused quartz to form b-cristobalite, wherein the concentration C of synthetically obtained SiO.sub.2 at a distance d from the surface is greater than the concentration of synthetically obtained SiO.sub.2 at a distance d2 from the surface, where d2 is greater than d. Multiple crystals can be grown while maintaining high crystal quality.

A fused quartz crucible for pulling a single crystal of silicon by the Czochralski technique, has an inner side with an inner layer of fused quartz that forms a surface, the inner layer being provided with a crystallization promoter which on heating of the fused quartz crucible during use, in crystal pulling, causes crystallization of fused quartz to form b-cristobalite, wherein the concentration C of synthetically obtained SiO.sub.2 at a distance d from the surface is greater than the concentration of synthetically obtained SiO.sub.2 at a distance d2 from the surface, where d2 is greater than d. Multiple crystals can be grown while maintaining high crystal quality.

A quartz glass crucible 1 includes: a quartz glass crucible body 10 having a cylindrical side wall portion 10a, a curved bottom portion 10b, and a corner portion 10c which has a larger curvature than that of the bottom portion 10b and connects the side wall portion 10a and the bottom portion 10b to each other; and an inner-surface coating film 13A which contains a crystallization accelerator and is formed on an inner surface 10i of the quartz glass crucible body 10, in which the inner surface 10i of the quartz glass crucible body 10 is under compressive stress. The quartz glass crucible has high durability even at a high temperature during a single crystal pull-up step and is capable of reducing a generation ratio of pinholes in a silicon single crystal.

A method for manufacturing fine surface roughness having an average pitch of 50 nanometers to 5 micrometers on a quartz glass substrate without preparing a mask prior to an etching process, the method comprising the steps of: making the quartz glass substrate undergo ion etching with argon gas in an ion etching apparatus, in which the quartz glass substrate is placed on a first electrode, the first electrode is connected to a high frequency power source and a second electrode is grounded; and making the quartz glass substrate undergo reactive ion etching with trifluoromethane (CHF.sub.3) gas or a mixed gas of trifluoromethane (CHF.sub.3) and oxygen in the ion etching apparatus in which the quartz glass substrate is placed on the first electrode, the first electrode is connected to the high frequency power source and the second electrode is grounded.

A method for producing rare earth metal-doped quartz glass includes the steps of (a) providing a blank of the rare earth metal-doped quartz glass, and (b) homogenizing the blank by softening the blank zone by zone in a heating zone and by twisting the softened zone along a rotation axis. Some rare earth metals, however, show a discoloration of the quartz glass, which hints at an unforeseeable and undesired change in the chemical composition or possibly at an inhomogeneous distribution of the dopants. To avoid this drawback and to provide a modified method which ensures the production of rare earth metal-doped quartz glass with reproducible properties, during homogenization according to method step (b), the blank is softened under the action of an oxidizingly acting or a neutral plasma.

A method for producing rare earth metal-doped quartz glass includes the steps of (a) providing a blank of the rare earth metal-doped quartz glass, and (b) homogenizing the blank by softening the blank zone by zone in a heating zone and by twisting the softened zone along a rotation axis. Some rare earth metals, however, show a discoloration of the quartz glass, which hints at an unforeseeable and undesired change in the chemical composition or possibly at an inhomogeneous distribution of the dopants. To avoid this drawback and to provide a modified method which ensures the production of rare earth metal-doped quartz glass with reproducible properties, during homogenization according to method step (b), the blank is softened under the action of an oxidizingly acting or a neutral plasma.