The instant invention is concerned with the production of glasses which are capable of being molded or otherwise shaped under pressure at temperatures not exceeding about 450.degree. C. Such glasses consist essentially, in mole percent as analyzed on the oxide basis, of at least 20% but less than 50% P.sub.2 O.sub.5, 15-45% R.sub.2 O, wherein R.sub.2 O consists of 0-45% Li.sub.2 O, 0-20% Na.sub.2 O, and 0-10% K.sub.2 O, and 0-20% RO, wherein RO consists of 0-10% MgO, 0-15% CaO, 0-20% SrO, and 0-20% BaO, with about 0.3-3% by weight F as analyzed in the final glass. Useful additions to the base compositions include PbO, La.sub.2 O.sub.3, ZnO, and B.sub.2 O.sub.3.