A film or sheet having a glass transition temperature below about 23 C. and a melting temperature greater than about 120 C. is prepared by first preparing a polyester composition of about 50 to about 95 weight percent of a base copolyester having a melting temperature of less than about 220 C. and exhibiting more than about 1 percent crystallinity after annealing for 2000 minutes at a temperature of which the base copolyester has a maximum crystallization rate; and about 5 to about 50 weight percent of a plasticizer suitable for use with the base copolyester. The polyester composition is formed into a film or sheet. During formation of the film or sheet or afterwards, crystallization is induced to provide a soft and flexible film or sheet.