Ok, I'm sure we've all seen how some particular US fighters have tinted glass canopies (I'm not sure what you would refer to the glass as), while others do not. Looking at the currently in-service aircraft jet fighters, the newest kids on the block have very noticeable and iconic canopy tints. The F-22 Raptor has its iconic orange/yellowish tint that, depending on the viewing angle, can sometimes look golden. The F-35 Lightning II has been seen sporting several different colored tints such as a faded pink, blue, or yellow. The F-16 Falcon and the F-18 Hornet both have a traditional black-colored tint. However, the F-15 Eagle does not seem to sport any canopy tints. Same with the F-14 Tomcat, although it is no longer in-service and the majority of the F-14 fleet has been dismantled.
So, here is my question: Why is it that only some US fighters have a tint while others do not?
My first assumption is that it would be to protect the advanced avionics from being viewed, while other, more outdated aircraft do not need as much protection of their avionics and flight systems, which would explain the F-15. However, I may be wrong about all of this and the tint may purely be to prevent the pilots from being blinded by the sun.
I have yet to find a definitive answer to the whole tinting phenomenon anywhere on the web, so I would like to see if anyone here would perhaps have the answer I'm looking for.