A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below T.sub.h, wherein T.sub.h is at least about 50? C., preferably 50? C.<T.sub.h<250? C.

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 quartz glass provides an opaque quartz glass having high light-shielding property, excellent mechanical strength and excellent cleaning resistance against hydrofluoric acid. By setting the maximum width of the amorphous bubbles existing in the opaque quartz glass to an average of 3 to 15 ?m and the density to 2.15 g/cm.sup.3 or more, the mechanical strength after baking and the cleaning resistance by hydrofluoric acid are improved. The opaque quartz glass has a whiteness at a thickness of 10 mm of 75 to 90%, the reflectance of light with a wavelength of 0.24 to 2.6 ?m at a thickness of 4 mm is 60 to 85%, and the bending strength after baking is 95 MPa. In addition, a foaming agent may be mixed in the opaque quartz glass. An opaque quartz glass having cleaning resistance against acid can be obtained.

A spherical inorganic oxide powder wherein a volume-based cumulative 50% diameter D50 is 4-55 ?m; and in a cross-section of a cured body containing an epoxy resin and the spherical inorganic oxide powder at a mass ratio of 2:1, when a total of 5000 particles with a maximum diameter of 51 ?m or larger are observed in a field of view at 100? magnification using a scanning electron microscope, a total number of air bubbles having a maximum diameter of 1 ?m or larger and smaller than 10 ?m is 40 or fewer and a total number of air bubbles having a maximum diameter of 10 ?m or larger is 30 or fewer.

A method for preparing quartz glass with low content of hydroxyl and high purity, includes providing silica powders including hydroxyl groups. The silica powders are dehydroxylated, which includes drying the silica powders at a first temperature, heating the silica powders up to a second temperature and introducing a first oxidizing gas including halogen gas, thereby obtaining first dehydroxylated powders, and heating the first dehydroxylated powders up to a third temperature and introducing a second oxidizing gas including oxygen or ozone, thereby obtaining second dehydroxylated powders. The second dehydroxylated powders are heated up to a fourth temperature to obtain a vitrified body. The vitrified body is cooled to obtain the quartz glass with low content of hydroxyl and high purity. The quartz glass prepared by the above method has low content of hydroxyl and high purity. A quartz glass with low content of hydroxyl and high purity is also provided.

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.

The present invention is a quartz glass fiber-containing prepreg including: (A) a quartz glass fiber; and (B) a curable resin composition, wherein at least one condition of conditions: (1) a dose of -ray contained in the quartz glass fiber is 0.005 c/cm.sup.2.Math.hour or smaller, and, each of metal ion contents of Na.sup.+, Li.sup.+ and K.sup.+ is 1 ppm or lower; (2) the quartz glass fiber contains the number of foams of 10 foams/m.sup.2 or smaller a unit area; and (3) the quartz glass fiber-containing prepreg has the common bending stiffness in the range of a thickness of 100 to 200 m measured by a method described in JIS R 3420:2013 of 500 N.Math.m.sup.2 or larger is satisfied. This provides a quartz glass fiber-containing prepreg that has particularly excellent dielectric characteristics, has excellent dielectric characteristics and the heat resistance, and/or has high handling property because of high bending stiffness characteristics.

A structure can comprise a substrate and a composite coating. The composite coating can be formed over a surface of the substrate. The composite coating can include one or more nanoparticles within an oxide matrix. The nanoparticles can be formed of a temperature-dependent Mott insulator having a phase transition temperature. At a temperature below the phase transition temperature, the composite coating can transmit light in a first wavelength range, and at a temperature above the phase transition temperature, the composite coating can block light in the first wavelength range. For example, the structure can be used as a smart 10 window to help regulate heating of building interiors due to solar radiation. The composite coating can be formed via a short-duration, high-temperature heating pulse, for example, at least 1500 K for less than 60 seconds.

A porous glass base material manufacturing system that does not require the manufacturing apparatus and building to be hazardous material-compatible and that can provide a stable supply of raw materials, even when organic siloxane raw material is used as raw materials to produce silica fine particles includes a raw material supplying apparatus and a porous glass base material manufacturing apparatus. The raw material supplying apparatus includes: a raw material tank in which organic siloxane raw material in a liquid state is stored and the remaining space is filled with inert gas; a liquid feed pump to pump the organic siloxane raw material from the raw material tank; a circulating piping and a branch piping through which the raw material pumped is passed; a liquid mass flow controller that controls the flow rate of organic siloxane raw material passed through the branch piping to a predetermined flow rate; and a vaporizer.

The present invention relates to a glass block including: Si; and at least one of Mg and Ca, and satisfying, in terms of mol %, 49.0% or less of B.sub.2O.sub.3, 11.5% or less of P.sub.2O.sub.5, 10.0 to 59.5% of a (=SiO.sub.2+B.sub.2O.sub.3+P.sub.2O.sub.5+GeO.sub.2), 66.5% or less of (a+Al.sub.2O.sub.3), 7.0% or less of Ga.sub.2O.sub.3, 0.44 or less of b (=Al.sub.2O.sub.3+Ga.sub.2O.sub.3+In.sub.2O.sub.3)/a, 20.0% or more of R.sup.2O (R.sup.2: alkaline earth metal), 50.0% or less of MgO, MgO?BaO, CaO?BaO, SrO?BaO, MgO?SrO, CaO?SrO, 1.2% or less of R.sup.1.sub.2O (R.sup.1: alkali metal), 4.8% or less of TiO.sub.2 or ZrO.sub.2, 9.5% or less of MnO.sub.2, 11.8% or less of ZnO, 0.067 or less of Ta.sub.2O.sub.5/SiO.sub.2, 15.0% or less of an impurity element, and 0.20 or less of F/O.