Music CDs aren't burnt (except the Dixie Chicks). A die is used to stamp the pattern of pits into the top of the blank disc, a layer of aluminium is overlaid to refelect the laser, then a layer of lacquer to protect the aluminium. That's the advantage of knowing what you are going to put on from the outset. Mass-produced CDs have gone bad when the lacquer has failed to protect the reflective layer, either because it didn't cover it fully or because the ink of the label ate the lacquer away, and it has "bronzed" from oxidation.