Abstract: A method of manufacturing glass bodies, in which the starting material for the glass body, being monodispersed SiO.sub.2 particles (quartz-glass powder), is used to form an open-pore green body which is subjected to a purification process in which the impurities present in the green body react with a purifying gas which is heated to a temperature in the range from 600 to 900.degree. C., after which the green body is sintered, in which a two-stage heating-purification step is used, such that in the first stage SiO.sub.2 particles are heated until they are dense-sintered, i.e. they have no more micropores, and in the second stage the homogeneous open-pore green body formed from the dense-sintered SiO.sub.2 particles is purified in a known manner in the purification gaseous atmosphere and subsequently sintered.