Lead-bismuth glasses for acoustooptic and magnetooptic devices

A homogeneous glass composition having an index of refraction of at least about 2.1, a longitudinal sound velocity of less than about 4 mm/.mu.sec, an acoustic loss of less than about 6 db/cm at 20 MHz, a Verdet constant greater than about 0.10 min/Oe-cm at 0.63.mu. m and an optical loss of less than about 10% cm when measured at a wavelength between 1 and 2.mu.m said glass consisting essentially of:

• Composition Mole % ______________________________________ GeO.sub.2 5-32 B.sub.2 O.sub.3 1.5-18 PbO 30-60 Bi.sub.2 O.sub.3 10-41 ______________________________________
• wherein:
• Bi.sub.2 O.sub.3 +PbO .gtoreq. 65% mole
• and ##EQU3##