| 摘要 |
PURPOSE:To synthesize the preform at a high rate with a multiplepipe burner without causing cracking, etc., at the time of synthesizing the preform on the periphery of a glass rod with the soot formation method by specifying the angle between the center axis of the burner and the rotating shaft of a starting material. CONSTITUTION:Glass fine particles are synthesized on the periphery of the starting material 1 from its one end with the multiplepipe flame burner 2, the burner is relatively moved in parallel with the rotating shaft of the burner 2, and a porous glass preform 5 is synthesized. In this method, since the bulk density of the preform is increased as the angle theta between the center axis of the burner 2 and the rotating shaft of the starting material 1 is increased, the angle theta is controlled to 60-90 deg.. The bulk density is not effectively increased at <60 deg., and the taper of the growth surface 4 of the preform tends to unfavorably increase at >90 deg.. The bulk density higher than a specified value is required to make the preform hard to crack and to obtain an excellent glass in vitrification and dehydration, and the synthesis is carried out at a rate to obtain the bulk density in the specified range. |
