Abstract: A heating oven is provided for processing glass materials from which optical waveguide fibers are prepared. The oven includes a vertically oriented, elongated cylindrical muffle for receiving the glass material which is to be processed. The supporting structure for the upper end of the muffle is thermally independent of the supporting structure for the remainder of the oven. In this way, the expansion and contraction of the muffle can be compensated for independently of the expansion and contraction of the oven's main support frame.

Abstract: A heating oven is provided for processing glass materials, e.g., porous glass preforms, from which optical waveguide fibers are prepared. The oven includes a stationary elongated chamber, e.g., a silica muffle, for receiving the glass material which is to be processed. At least a portion of the chamber is surrounded by a stationary susceptor. The chamber is heated by moving an energized induction heating coil along a path parallel to the longitudinal axes of the susceptor and the chamber.

Abstract: A method for consolidating a porous glass preform is provided in which a preform is placed in a stationary elongated chamber and selected portions of the chamber, distributed along the chamber's length, are sequentially heated above the preform's sintering temperature. In certain preferred embodiments, the chamber is surrounded by an elongated susceptor and the heating is performed by moving an induction heating coil along a path parallel to the longitudinal axes of the susceptor and the chamber.

Abstract: A heating oven for processing glass materials from which optical waveguide fibers are prepared is provided which comprises:(a) an elongated chamber for receiving the glass material to be processed; and(b) means for heating the chamber, said means comprising an elongated susceptor, the longitudinal axis of the susceptor being parallel to the longitudinal axis of the chamber, an induction heating coil, means for moving the induction heating coil along a path parallel to the longitudinal axes of the susceptor and the chamber, and means for energizing the induction heating coil.