Go to the US patent web site and search for polaroid patents granted to Edwin Land, or use www.freepatentsonline.com for searches.

A google search might start you off, as well as searches of SPSE journals where Edwin Land published first. I have read some of his papers and heard him speak on this. Also, George Eastman House has this sort of thing in their archives.

A more 'concentrated' source exists at GEH.