A composition containing a non-flammable chlorofluoro-olefin copolymer having a crystallinity index less than about 10% and a weight-average molecular weight greater than about 1,000,000 daltons, wherein the copolymer has at least two comonomer units of the formula: CX.sub.2 CYA wherein each X is independently selected from H, Cl and F; Y is selected from H, Cl, F, O(CZ.sub.2).sub.n CZ.sub.3, (CZ.sub.2).sub.n CZ.sub.3, (OCZ.sub.2 CZ.sub.2).sub.n CZ.sub.3 and (O(CZ.sub.2).sub.n).sub.n CZ.sub.3, wherein each n is independently from about 1 to about 12 and each Z is independently selected from H, Cl and F; and A is selected from H, Cl and F, provided that for at least one comonomer unit, at least one of A, Y, either X or any Z is Cl. Substrates coated with the copolymer compositions are also disclosed.