Due
to the heat sensitive decay of the dye, after time
the CD-R will reach a stage where the darkened areas
are indistinguishable from those that are not resulting
in the disc becoming useless.
Kodak have done some extensive testing on the lifetime
of their “Ultima” CD-R media using an
accelerated ageing process. They first found the
lifetime at a higher temperature of 80oC and used
the Arrhenius equation to estimate the lifetime
at room temperature.
|
Arrhenius
equation: 
t = disc lifetime
A = pre-exponential time constant
E = activation energy
k = Boltzmann constant
T = absolute temperature |
|
The trouble with this equation is that either one
of A and E must be known or assumed. Kodak have
estimated the activation energy based on empirical
evidence and arrived at 2.10eV. This gives the lifetime
as over 5,000 years! |
Due to the assumptions made this is not an accurate
method but even with a lot of error Kodak have manages
to show that their CD-Rs will have a lifetime of
well over the warranted 100 years. |
