Fiberizable zinc-phosphate glass compositions

A method of making glass fibers comprising the steps of:

• a. melting a batch for a glass composition consisting essentially, expressed in terms of mole percent on the oxide basis, of at least 65% total of 10-55% ZnO, 28-40% P.sub.2 O.sub.5, 0.2-5% MoO.sub.3, 10-35% R.sub.2 O, wherein R.sub.2 O consists of at least two alkali metal oxides in the indicated proportions selected from the group consisting of 0-25% Li.sub.2 O, 0-25% Na.sub.2 O, and 0-25% K.sub.2 O and up to 35% total of optional ingredients in the indicated proportions selected from the group consisting of 0-10% Al.sub.2 O.sub.3, 0-15% B.sub.2 O.sub.3, 0-15% Al.sub.2 O.sub.3 +B.sub.2 O.sub.3, 0-15% Cu.sub.2 O, 0-5% F, 0-25% Sb.sub.2 O.sub.3, 0-35% PbO, 0-35% SnO, 0-35% PbO+SnO, 0-5% ZrO.sub.2, 0-4% SiO.sub.2, 0-20% MgO+CaO+SrO+BaO+MnO, 0-20% MgO, 0-20% CaO, 0-20% SrO, 0-20% BaO and 0-10% MnO, and 0-5% rare earth metal oxide;
• b. fining the glass melt;
• and,
• c. drawing fibers from the glass melt at a temperature at which the melt has a viscosity of about 10.sup.6 to 10.sub.8 poise.