Did you use rewritable or write-once disks? They are both based on a totally different -what's-the-word- thingy.
CDR's are based on an organic material that gets 'burned' by the laser, and turns 'black' (non-reflective). After a very long time the material burns totally. (The same way as paper turns yellow and even black after a very long time. It 'burns' even at room-temperature.)
CDRW's are based on a cristalline material. The laser melts it, and it cools very fast, so that it doesn't have the time to cristallize again. It leaves a amorph (non-reflective) space. In time, it will cristallize again, but very slowly. (about 40 years at least, if I remember correctly, and if you live in
the sahara...

) This proces can be fastened by the laser on half-power, heating it untill just under it's melting point.
So you see: these aren't everlasting recordings. What is meant is that they don't degrade by playback, as vinyl does! They will degrade over time. But you can play them as much as you want. (This isn't true either. During playback they warm up too, thus fastening the degradation-process...)
Roel (wasting 8hours/day testing proto-types of future CD-DVD (encoder/decoder) chips.)