The libraries of the Southeastern Pennsylvania Consortium for Higher Education (SEPCHE) all will allow you to use their resources and even check material out, as if you were one of their students. Contact them ahead of time, using the information below, to be sure the resource you are looking for is available.
The Tri-State College Library Cooperative (TLCL) welcomes students of Chestnut Hill College when armed with a signed "Letter of Introduction." Head over to the library to request a letter before you visit a college on the list linked here that isn't also a member of SEPCHE.
With a library card from one of the area's library systems, you can use their resources online.