Purifying process of fluoride glass
AssigneeKokusai Denshin Denwa Kabushiki Kaisha
InventorsTetsuya Nakai, Yoshinori Mimura, Osamu Shinbori, Hideharu Tokiwa
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Abstract
A fluoride glass for infrared optical transmission fiber is purified for dehydration and deoxidation to reduce transmission loss by reacting melted fluoride glass with NF.sub.3 gas at temperature between 500.degree. C. and 800.degree. C. No scattering loss is increased by the present purification as decomposed product in the reaction does not precipitate.
Claims9
A purifying process for dehydration and deoxidation of fluoride glass comprising the step of heating fluoride glass to temperature between 500.degree. C. and 800.degree. C. to melt the glass in atmosphere of fluoride nitrogen (NF.sub.3) to react radical fluorine atom dissociated from NF.sub.3 with hydroxyl group, complex ion and oxide included in the fluoride glass.
A purifying process for dehydration and deoxidation of fluoride glass comprising the steps of;
- heating fluoride glass around 800.degree. C. for at least 30 minutes to melt that fluoride glass,
- decreasing the temperature to around 700.degree. C.,
- flowing gas including NF.sub.3 on melted fluoride glass by rate of about 3 liter/minute for at least 30 minutes, and
- cooling the fluoride glass by rate of about 30.degree. C./minutes.
Dependencies are inferred from the claim text.