Can someone explain the reactions of the discoloration for polyimide and
soldermask?  These materials would continue to cure with exposure to
extended heat cycles, what is the mechanism of the discoloration?  The
materials continue to cross-link, which in the case of soldermask leads to
brittle mask, but what other reactions are taking place and why the color
change?

This just seems like a good day for a chemistry lesson!

Thanks,
Jana Carraway
MSEI

PS - Hans Hinner, how does getting married make your a spud?  I come from
Idaho, the potato state, and hence am a "spud"...regardless of marital
state!

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