Illuminating devices are disclosed having plastic light-transmitting article(s) formed from a thermoplastic composition including a polycarbonate having repeating structural carbonate units according to the formula: in which at least 60 percent of the total number of R1 groups contain aromatic moieties and the balance thereof are aliphatic, alicyclic, or aromatic. The composition also includes an epoxy additive having at least two epoxy groups per molecule and a phenolic diphosphite derived from pentaerythritol. The thermoplastic composition exhibits a dE (2000 hrs.) value of less than 1.5 after 2000 hours of heat aging at 130° C., measured according ISO 11664-4:2008(E)/CIE S 014-4/E:2007 using CIE illuminant D65 and a 2.5 mm thick molded plaque of the thermoplastic composition.