[sdiy] Do LDRs and/or LEDs age?

[Paul Perry]

>Looking at Paul's awesome Buchla pictures got me to wondering about the 
>lifetime and ageing of LDR/diode control devices - Varactrols, CLM6000, 
>home-brew, and otherwise.

I have some CLM6000 that I bought from a surplus guy, old stock from when 
they first came out.
About 20% seemed to be 'out of spec', as though not enough output from
the led (and I can't imagine any kind of amorphous semi going high in
resistance with age).
I vaguely remember reading once that early leds sometimes had 
bodies that allowed warer vapor to diffuse in slowly, with resulting 
decreasing light output.
No idea whether this is true or not, but it seems a plausible mechanism..
what do the semi fabrication experts here think?

paul perry melb australia