TREATMENT OF GLASS SURFACE

摘要

PROBLEM TO BE SOLVED: To obtain a tellurite glass for an optical fiber contg. having not many crystals on the glass surface and having high mechanical strength by bringing an aq. soln. contg. hydrofluoric acid at a specified concn. into contact with a glass surface under aeration and agitation and etching the surface. SOLUTION: An aq. soln. contg. hydrofluoric acid at 0.36-0.72 mol/l concn. or an aq. soln. contg. hydrofluoric acid at 0.36-0.54 mol/l concn. and nitric acid at <=0.14 mol/l concn. is poured into a glass holder as an etching soln. and bubbles are generated in the etching soln. by feeding gaseous argon at an adjusted flow rate from a gas feeder through a glass filter. An oxide glass rod fixed on a sample holder made of Teflon is put in the etching soln. and etched for 5-20 min. Other inert gas such as helium or nitrogen may be fed. The etched glass rod is washed and dried.