tough and are useful as glazing materials or molding compounds and are capable of maintaining dimensional stability at temperatures approaching their glass transition temperature application_number US 40090282 A description it has been found that diprimary dialcohol polyesters such as polyethylene arylates and more specifically polyethylene terephthalate are not compatible with bisphenol a polycarbonates and that by co reacting a blend or melt mix of the two they can be compatibilized according to the process of the subject invention a melt mix of high molecular weight polyethylene arylate and a high molecular weight bisphenol a polycarbonate is prepared by extrusion through a simple extruder to yield an intimate blend of the two polymers the blend is not compatible has two glass transition temperatures tg and is only partially soluble in polycarbonate solvents such as chloroform and tetrachloroethane and the polyethylane arylate has a tendency to crystallize when this blend is heated to a temperature of about 260 u00b1 20 u00b0 c with stirring under vacuum of less than 1 millimeter of pressure mercury for about 30 60 minutes the resulting product has gained in molecular weight as determined by measuring its intrinsic viscosity it now exhibits only one tg between the respective tg 39 s of the two components it no longer.