Solution terpolymerization of styrene, acrylonitrile and chromium acrylate has been carried out in dimethylformamide at 85-degrees-C using styrene-arsenic sulfide complex as radical initiator. H-1 nuclear magnetic resonance (n.m.r.), infra-red (i.r.) and elemental analysis have been used to characterize the terpolymer. Data from H-1 n.m.r., elemental analysis and gravimetric analysis have been used to evaluate terpolymer composition. Reactivity ratios (calculated from Finemann-Ross method as r1(Sty) = 5 +/- 2 r2(AN + CrA) = 0.15 + 0.02) and composition confirm its random origin. The terpolymer was highly thermally stable and has a glass transition temperature of 96-degrees-C as evaluated from differential scanning calorimetry studies.