Optically anisotropic melt forming copolyesters

A copolyester consisting essentially of (a) Units I, II, III and IV or (b) Units I, II and III, said units having the structural formulas:

• ##STR3## where x is selected from the group consisting of hydrogen, halo-, lower alkyl, and aryl, Y is selected from the group consisting of oxygen and carbonyl and wherein said copolyesters consisting essentially of Units I, II, III and IV contain from about 10 to 15 mole % of Unit I, from about 10 to 20 mole % of Unit II, from about 10 to 15 mole % of Unit III and from about 50 to 70 mole % of Unit IV;
• and wherein said copolyesters consisting essentially of Units I, II and III contain from about 40 to 45 mole % of Unit I, from about 40 to 50 mole % of Unit II and from about 10 to 15 mole % of Unit III.