Glass has a refractive index of 1.55 or more, and has, in an x-ray absorption fine structure (XAFS) analysis of platinum, a peak intensity ratio expressed by A.sub.max/A.sub.ave of 1.13 or more, where A.sub.max denotes a maximum value of a white line within an energy range of 13,270 eV to 13,290 eV, and A.sub.ave denotes an average absorption in an energy range of 13,290 eV to 13,390 eV.

The present disclosure provides a solidifying method of a radionuclide. The solidifying method of the radionuclide includes operations of: providing a low melting point glass including Bi.sub.2O.sub.3, B.sub.2O.sub.3, ZnO and SiO.sub.2; providing a glass mixture mixing a mixture to be treated containing a hydroxide of radionuclide and BaSO.sub.4 and the low melting point glass; and heating the glass mixture.

One aspect relates to a process for the preparation of a quartz glass body. The process includes providing silicon dioxide particles, making a glass melt out of the silicon dioxide particles in an oven and making a quartz glass body out of at least part of the glass melt. The oven has a gas outlet through which gas is removed from the oven, wherein the dew point of the gas on exiting the oven through the gas outlet is less than 0° C. 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 of the quartz glass body.

One aspect relates to a process for the preparation of a quartz glass body. The process includes providing silicon dioxide particles, making a glass melt out of the silicon dioxide particles in an oven and making a quartz glass body out of at least part of the glass melt. The oven has a gas outlet through which gas is removed from the oven, wherein the dew point of the gas on exiting the oven through the gas outlet is less than 0° C. 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 of the quartz glass body.

A glass comprising at least one oxide of Si and a di- or higher-valent metal element, the glass containing no bubbles with diameters of more than 0.1 mm, wherein an occupied area fraction of bubbles with diameters of 0.1 mm or less is 0.05% or less. A. semiconductor production apparatus and a liquid crystal production apparatus comprising a glass member comprising this glass. A method for producing a glass, comprising the steps of (1) placing raw material powders for at least one oxide of Si and a di- or higher-valent metal element in a container, mixing the raw material powders together and then melting the mixture by heating under reduced pressure to obtain a melt; (2-1) pressurizing the melt in a He gas atmosphere, or (2-2) heating the melt in an inert gas atmosphere other than a He gas atmosphere and then pressurizing the melt in the inert gas atmosphere; and (3) cooling the melt.

An optical glass may be a phosphate based glass containing at least any one of oxides selected from TiO2, Nb2O5, WO3, and Bi2O2. The total content (HR) of the TiO2, Nb2O5, WO3, and Bi2O2 may be 35 mol % or above, the noble metal content may be less than 2.0 ppm, and the βOH value, given by the following general formula, may be 0.1 mm-1 or above: βOH=−[ln(B/A)]/t.

An optical glass may be a phosphate based glass containing at least any one of oxides selected from TiO2, Nb2O5, WO3, and Bi2O2. The total content (HR) of the TiO2, Nb2O5, WO3, and Bi2O2 may be 35 mol % or above, the noble metal content may be less than 2.0 ppm, and the βOH value, given by the following general formula, may be 0.1 mm-1 or above: βOH=−[ln(B/A)]/t.

The present invention provides for synthesizing high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a two-zone furnace and multiple fining steps. The top and bottom zones are initially heated to the same temperature, and then a temperature gradient is created between the top zone and the bottom zone. The fining and cooling phase is divided into multiple steps with multiple temperature holds.

The present invention provides for synthesizing high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a two-zone furnace and multiple fining steps. The top and bottom zones are initially heated to the same temperature, and then a temperature gradient is created between the top zone and the bottom zone. The fining and cooling phase is divided into multiple steps with multiple temperature holds.

A production apparatus making continuously curved crystalline glass as a cover or container includes a melting device, a drainage device, a molding device, and a crystallizing device. The melting device melts glass raw material to form a glass melt. The drainage device drains the glass melt to the molding device. The molding device includes a rotating table and a plurality of molding molds thereon. Each molding mold can be moved toward or away from the drainage device by the rotating table. Each molding mold has a molding cavity. At least one part of the molding cavity includes a plane, and at least one part of the molding cavity includes a curved surface to extrude the glass melt with such different surface forms. The crystallizing device crystallizes the curved glass member to achieve the curved crystallized glass member. A method for manufacturing such glass is also provided.