Blow molded, oriented plastic bottle and method for making same

A self-supporting biaxially oriented plastic container blow molded from a parison across the thickness of its sidewall an outwardly radially decreasing temperature gradient within the orientation temperature range of and made from a glassy, essentially non-crystalline thermoplastic polymeric material which is capable of being biaxially oriented during blow molding, said container having a tubular sidewall with inner and outer surfaces, said sidewall having inner, middle and outer portions and being characterized in that in an axial zone thereof the percentage variation of the circumferential orientation release stress from said inner portion to said outer portion is less than about 4% per mil of sidewall thickness, said percentage variation being determined by multiplying 100 by a fraction in which the numerator is the difference between the orientation release stresses at said inner and outer portions and in which the denominator is the average of the orientation release stresses in said inner, middle and outer portions multiplied by the radial distance in mils between the centerlines of the inner and outer portions.