Re: Do Opaque materials undergo any change after absorbtion of light ?

You are basically correct: electrons interact with the incoming light and 
go to another quantum state. The term “permanent” does not always apply, 
however.  Sometimes the optically excited state of the electron is long 
lived, and in such cases part of the energy of the photon becomes stored 
in the material.  More generally the excited state of the electron decays 
to a lower energy state via the emission of lower frequency light, or 
acoustic excitation of the material. In this case the energy of the light 
can go to heat or  to other frequencies of light, or even converted into 
electrical current as is the case with a photo-voltaic device.   The 
energy of the light can also, as you suggest, be converted into chemical 
energy.  This is the case with plants, but even then, only part of the 
light energy is stored, and part turned into heat.