The above results indicate that the three clays studied in this work cause the degradation of polycarbonate during the melt processing of the nanocomposites. The effect depends on the organic modification of the clay, being C15 the most active of the three clays. The results of the fluorescence study appear to indicate that the clays favor the formation of fluorophores which may be, at least in part, phenolic compounds. The results obtained in the thermogravimetric analysis reveal a degradation during the com- pounding that causes the appearance of fragments of lower mo- lecular weight and, hence, lower thermal stability. Finally the UV spectroscopic analysis appears to indicate the hydrolysis of the polycarbonate molecules, with formation of phenolic units. All these results are coherent.