Abstract
Silica gel fibers made from TEOS by the sol-gel method were preheat-treated in the temperature range of 200 to 500°C, and were converted to silica glass fibers by further heat-treating up to 800°C.
Tensile strength of the glass fiber preheat-treated at 300°C for 10h was about 1.4 times larger than that obtained without the preheat treatment.
Such an effect of the preheat treatment on the tensile strength of the sol-gel-derived silica glass fiber was discussed in relation to the reconstructive change of overall atomic scale-structure of the gel network consisting of OH-terminated 4-membered siloxane rings to three-dimensional network constructed with 6-membered siloxane rings which occurs in the starting gel fibers at 200-500°C and often causes the destruction of the silica network when heat-treated rapidly. As a result, it was considered that the preheat treatment made the reconstructive change moderate to avoid the destruction of the network.
