Skylight secondary-glass installation?

We have a single pane, (very inefficient) skylight with both heat loss in the winter and heat gain in the summer. We would like to install a second pane of glass as close to the first pane as possible for more energy efficency here in Boston, Massachusetts, USA. We have been told to contact a local glass manufacturer for residential glass. We have been told that they can sell us dead-light glass or laminated glass. How do we search for a local glass dealer who will work with us. Everything we can think of is not helping us find a list of residential glass companies. Thanks.