Abstract: A new, simplified method of fabricating optically transparent fluoride glasses containing ZrF.sub.4 and/or HfF.sub.4 has been developed which relies on a high vacuum pre-treatment for surface dehydration, melting in a rigorously inert argon atmosphere, and incorporation of a nonvolatile metallic oxidant in the melt such as InF.sub.3 and SnF.sub.4. Previous method for making these glasses have relied on either addition of ammonium bifluoride into the batch materials, or melting in an oxidizing atmosphere (so-called reactive atmosphere processing or RAP); both of these latter techniques have significant drawbacks.

Abstract: A new, simplified method of fabricating optically transparent fluoride glasses containing ZrF.sub.4 and/or HfF.sub.4 has been developed which relies on a high vacuum pretreatment for surface dehydration, melting in a rigorously inert argon atmosphere, and incorporation of a nonvolatile metallic oxidant in the melt such as InF.sub.3 or SnF.sub.4. Previous methods for making these glasses have relied on either addition of ammonium bifluoride into the batch materials, or melting in an oxidizing atmosphere (so-called reactive atmosphere processing or RAP); both of these latter techniques have significant drawbacks.