Abstract: A method for producing a large quartz-glass pipe is provided. In a first forming step, an intermediate cylinder made of quartz glass and having an intermediate-cylinder wall thickness and outside diameter is formed by using a forming tool and is then cooled. In a second shaping step, at least one length segment of the cooled intermediate cylinder is fed to a heating zone, heated to a softening temperature zone by zone therein, and, while rotating about the longitudinal axis of the intermediate cylinder, shaped into the large quartz-glass pipe having a final wall thickness and outside diameter. The quartz glass is synthetically produced and has an average hydroxyl group content of 10 ppm by weight or less. If the intermediate cylinder is divided into length segments of 1 cm, adjacent length segments have a difference of less than 2 ppm by weight in the average hydroxyl group content thereof.

Abstract: The invention relates to a method for the production of a transparent coating composition which is based essentially on a polycondensation reaction. The coating composition produced by this method is based on a completely through-condensed inorganic silicate network whilst the organic network is not yet formed. The invention also relates to a method for coating substrates with coating compositions of this type with formation of a coated substrate in which, in addition to the inorganic network, the organic network is also formed by the curing process. Coating compositions of this type and coated substrates are used widely in all optical fields of application.

Abstract: The invention relates to a process for producing thin, semiconducting films photosensitized by one or more chromophores, which comprises at least one cycle comprising, in succession, the following steps: a) a step of depositing, on a support, at least one film of a solution obtained by sol-gel polymerization of one or more precursors of a semiconducting oxide or semiconducting oxides, said semiconducting oxide or oxides being chosen from metal oxides, metalloid oxides and mixtures thereof; b) a drying step carried out on the film obtained at a); c) an acid, basic or neutral treatment step carried out in liquid or gaseous medium on the film obtained at b); and d) a step of photosensitizing the film obtained at c) by one or more chromophores, by bringing this film into contact with a solution containing the chromophore(s). Application to the production of electrodes for photovoltaic cells and to light-emitting diodes.