Patent ID: 6799442
Filing Date: 2004-10-05
Classification: C03B

Abstract:
Sol-gel process for the production of vitreous body articles containing an incompressible insert comprising:a) providing an incompressible insert; b) providing a container which can retain said incompressible insert in rigidly fixed position to define a space between an inside surface of said container and an external surface of said insert, and which can be rotated around an axis of said insert; c) fixing said insert to the inside of said container is such a way as to rotate said insert as one with said container; d) filling said space with a sol and closing said container; e) rotating said container containing said sol and said insert around the axis of the insert for a sufficient period of time necessary to complete gelling of said sol; f) opening said container and extracting the composite comprising a wet gel adhering to said incompressible insert; g) drying said wet gel, whereby said container in step e) is placed in rotation at such speed that the product P of the angular velocity &ohgr; measured in radians per second (rad/s) and the radius r of the insert measured in centimeters (cm) is between about 20 and about 250 radÃ—cm/s and adding a step of glass densification of the dry gel adhering to said incompressible insert by means of heat treatment at a temperature within the rankle of about 800 to about 1400Â° C.