Optical fluorophosphate glass and process of making same

In a process of producing an optical fluorophosphate glass having an index of refraction n.sub.e within the range from about 1.47 to about 1.54, Abbe number .nu..sub.e within the range of from about 84.1 to about 51.0, and a high positive anomalous partial dispersion .DELTA..nu..sub.e within the range of from about +10.0 to about +21.0, said process comprising the steps of

• a. melting a mixture essentially consisting of the following glass-forming components, in weight percent:
• METAPHOSPHATE COMPONENTS (A):
• 0% to 9% of cadmium metaphosphate (Cd(PO.sub.3).sub.2)
• 0% to 25% of lead metaphosphate (Pb(PO.sub.3).sub.2)
• 0% to 33% of antimony trimetaphosphate (Sb(PO.sub.3).sub.3)
• 0% to 22% of lanthanum metaphosphate (La(PO.sub.3).sub.3)
• 0% to 5% of germanium tetrametaphosphate (Ge(PO.sub.3).sub.4)
• 0% to 25% of titanium tetrametaphosphate (Ti(PO.sub.3).sub.4)
• 0% to 25% of niobium pentametaphosphate (Nb(PO.sub.3).sub.5)
• 0% to 25% of molybdenum hexametaphosphate (Mo(PO.sub.3).sub.6)
• 0% to 25% of tungsten hexametaphosphate (W(PO.sub.3).sub.6)
• 0% to 9% of lanthanum orthophosphate (LaPO.sub.4);
• FLUORIDE COMPONENTS (B):
• 3% to 7% of magnesium fluoride (MgF.sub.2)
• 5% to 19% of calcium fluoride (CaF.sub.2)
• 0% to 11% of strontium fluoride (SrF.sub.2)
• 0% to 34% of barium fluoride (BaF.sub.2)
• 0% to 4% of cadmium fluoride (CdF.sub.2)
• 21% to 23% of aluminum fluoride (A1F.sub.3)
• 0% to 10% of bismuth trifluoride (BiF.sub.3);
• COMPLEX FLUORIDE COMPONENTS (C):
• 0% to 6% of potassium hydrogen fluoride (KHF.sub.2)
• 0% to 15% of potassium titanium hexafluoride (K.sub.2 TiF.sub.6)
• 0% to 24% of barium titanium hexafluoride (BaTiF.sub.6), the total sum of the alkaline earth metal fluorides in said mixture being between about 40% and about 58%, the total sum of all fluorides in said mixture being between about 67% and about 80%, and the total sum of the metaphosphates being between about 16% and about 33%,
• b. homogenzing the molten mixture,
• c. cooling said resulting homogenized melt, and
• d. pouring the cooled melt into preheated molds.

A batch composition for producing a fluorophosphate glass having an index of refraction n.sub.e within the range of from about 1.47 to about 1.54, an Abbe number .nu..sub.e within the range of from about 84.1 to about 51.0, and a high positive anomalous partial dispersion .DELTA..nu..sub.e within the range of from about +10.0 to about +21.0, said composition essentially consisting of the following glass-forming comonents, in weight percent.

• METAPHOSPHATE COMPONENTS (A):
• 0% to 9% of cadmium metaphosphate (Cd(PO.sub.3).sub.2)
• 0% to 25% of lead metaphosphate (pb(PO.sub. 3).sub.2)
• 0% to 33% of antimony trimetaphosphate (Sb(PO.sub.3).sub.3)
• 0% to 22% of lanthanum metaphosphate (La(PO.sub.3).sub.3)
• 0% to 5% of germanium tetrametaphosphate (Ge(PO.sub.3).sub.4)
• 0% to 25% of titaniumm tetrametaphosphate (Ti(PO.sub.3).sub.4)
• 0% to 25% of niobium pentametaphosphate (Nb(PO.sub.3).sub.5)
• 0% to 25% of molybdenum hexametaphosphate (Mo(PO.sub. 3).sub.6)
• 0% to 25% of tungsten hexametaphosphate (W(PO.sub.3 ).sub.6)
• 0% to 9% of lanthanum orthophosphate (LaPO.sub.4);
• FLUORIDE COMPONENTS (B):
• 3% to 7% of magnesium fluoride (MgF.sub.2)
• 5% to 19% of calcium fluoride (CaF.sub.2)
• 0% to 11% of strontium fluoride (SrF.sub.2)
• 0% to 34% of barium fluoride (BaF.sub.2 )
• 0% to 4% of cadmium fluoride (CdF.sub.2)
• 21% to 23% of aluminum fluoride (A1F.sub.3)
• 0% to 10% of bismuth trifluoride (BiF.sub.3)
• COMPLEX FLUORIDE COMPONENTS (C):
• 0% to 6% of potassium hydrogen fluoride (KHF.sub.2)
• 0% to 15% of potassium titanium hexafluoride (K.sub.2 TiF.sub.6)
• 0% to 24% of barium titanium hexafluoride (BaTiF.sub.6),
• the sum total of the alkaline earth metal fluorides in said mixture being between about 40.0% and about 58.0%, the sum total of all fluorides being between about 67.0% and about 80.0%, and the sum total of the metaphosphates being between about 16.0% and about 33.0%.