Thermal radiation greatly affects the transient thermal response of translucent materials in many practical applications, such as radiative heat shields and ignition and flame spreads for translucent plastics. However, because of the complexities that transients impose, less work has been done on the transient analysis of combined radiation-concluction heat transfer than on steady-state analysis. In this study, the transient heat transfer analysis of a polycarbonate (PC) layer was done with the use of the two-flux method and implicit finite difference formulations. The radiative and conductive properties of PC available in the literature, together with computer implementation prepared on the basis of the two-flux method and implicit finite difference formulations, were used to obtain the transient thermal response of a PC layer. On the basis of these results, we show that, compared to the conduction-alone case, the PC layer responded faster when radiation effects were considered. It is also shown that the internal reflectivity of boundaries had a great effect on the thermal response of the layer, whereas the thermal conductivity had a minor influence. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 3313-3321, 2009