One aspect is a process for the preparation of a quartz glass body including providing a silicon dioxide granulate wherein the provision includes providing silicon dioxide powder, and processing the silicon dioxide powder to obtain a silicon dioxide granulate. The silicon dioxide granulate has a larger particle diameter than the silicon dioxide powder. The processing includes processing the silicon dioxide powder to obtain a silicon dioxide granulate I, wherein the silicon dioxide granulate I has a first carbon content wC(1), treating the silicon dioxide granulate I with a reactant to obtain a silicon dioxide granulate II with a further carbon content wC(2), wherein the further carbon content wC(2) is less than the first carbon content wC(1), 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.

One aspect relates to a process for the provision of a quartz glass body, including providing a silicon dioxide granulate, making a glass melt from the silicon dioxide granulate in an oven and making a quartz glass body from at least part of the glass melt. The oven includes a hanging metal sheet crucible. One aspect also 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 obtainable by processing the quartz glass body further.

One aspect relates to a process for the preparation of a quartz glass body. The process includes providing a silicon dioxide granulate, making a glass melt out of the silicon dioxide granulate, and making a quartz glass body out of at least a part of the glass melt. In one aspect, providing a silicon dioxide granulate includes providing of a silicon dioxide powder and processing of the powder to obtain a silicon dioxide granulate including the spray drying of a silicon dioxide slurry using a nozzle. The nozzle has a contact surface to the slurry made of glass, plastic or a combination thereof. Furthermore, one aspect relates to a quartz glass body obtainable by this process. Furthermore, one aspect relates to the preparation of a silicon dioxide granulate. One aspect also relates to a light guide, an illuminant, and a formed body, made from processing of the quartz glass body.

One aspect relates to a process for the preparation of a quartz glass body. The process includes providing a silicon dioxide granulate, making a glass melt out of the silicon dioxide granulate, and making a quartz glass body out of at least a part of the glass melt. In one aspect, providing a silicon dioxide granulate includes providing of a silicon dioxide powder and processing of the powder to obtain a silicon dioxide granulate including the spray drying of a silicon dioxide slurry using a nozzle. The nozzle has a contact surface to the slurry made of glass, plastic or a combination thereof. Furthermore, one aspect relates to a quartz glass body obtainable by this process. Furthermore, one aspect relates to the preparation of a silicon dioxide granulate. One aspect also relates to a light guide, an illuminant, and a formed body, made from processing of the quartz glass body.

The invention relates to a process for preparing a quartz glass body comprising the process steps i.) Providing a silicon dioxide granulate, ii.) Making a glass melt from the silicon dioxide granulate in a melting crucible, and iii.) Making a quartz glass body from at least a part of the glass melt, wherein the melting crucible is comprised in an oven and is made of at least one material comprising tungsten or molybdenum or a combination thereof. The invention further relates to a quartz glass body which can be obtained by this process. Further, the invention relates to a light guide, an illuminant and a formed body, each of which can be obtained by processing the quartz glass body further.

One aspect relates to a light guide comprising a jacket and one or more cores, wherein the jacket surrounds the cores. Each core has a refractive index profile perpendicular to the maximum extension of the core, wherein at least one refractive index n.sub.K of each refractive index profile is greater than the refractive index n.sub.M1 of the jacket. The jacket is made of silicon dioxide and has an OH content of less than 10 ppm, a chlorine content of less than 60 ppm, and an aluminium content of less than 200 ppb. One aspect also relates to a silicon dioxide granulate I, characterized by a chlorine content of less than 200 ppm and an aluminium content of less than 200 ppb, in each case based on the total weight of the silicon dioxide granulate I.

One aspect relates to a light guide comprising a jacket and one or more cores, wherein the jacket surrounds the cores. Each core has a refractive index profile perpendicular to the maximum extension of the core, wherein at least one refractive index n.sub.K of each refractive index profile is greater than the refractive index n.sub.M1 of the jacket. The jacket is made of silicon dioxide and has an OH content of less than 10 ppm, a chlorine content of less than 60 ppm, and an aluminium content of less than 200 ppb. One aspect also relates to a silicon dioxide granulate I, characterized by a chlorine content of less than 200 ppm and an aluminium content of less than 200 ppb, in each case based on the total weight of the silicon dioxide granulate I.

The invention relates to a process for the preparation of a quartz glass body comprising the process steps i.) 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, ii.) Making a glass melt out of silicon dioxide granulate and iii.) Making a quartz glass body out of at least part of the glass melt, wherein the melting crucible has at least one inlet and at least one outlet, wherein at least part of the glass melt is removed via the melting crucible outlet. The invention further relates to a quartz glass body which is obtainable by this process. The invention further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

The invention relates to a process for the preparation of a quartz glass body comprising the process steps i.) 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, ii.) Making a glass melt out of silicon dioxide granulate and iii.) Making a quartz glass body out of at least part of the glass melt, wherein the melting crucible has at least one inlet and at least one outlet, wherein at least part of the glass melt is removed via the melting crucible outlet. The invention further relates to a quartz glass body which is obtainable by this process. The invention further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

The invention relates to a process for the preparation of a quartz glass body comprising the process steps i.) 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 m.sup.2/g, ii.) Making a glass melt out of silicon dioxide granulate in an oven and iii.) Making a quartz glass body out of at least part of the glass melt, wherein the oven has at least a first and a further chamber connected to one another via a passage, wherein the temperature in the first chamber is lower than the temperature in the further chambers. The invention further relates to a quartz glass body which is obtainable by this process. The invention further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.