A method of making an optical film comprises heating the optical film
comprising greater than or equal to 80 wt. % polycarbonate to a
sufficient temperature to stretch the optical film, wherein the weight
percent is based on a total weight of the optical film; and stretching
the optical film, wherein a resulting stretched optical film has a linear
CTE measured in a direction parallel to a stretching direction of less
than or equal to 50.times.10.sup.-6 cm/cm/.degree. C.