Noise reduction of a hollow core door versus a french (glass panes) door
Look at the STC rating of the door. The higher the number the better the sound proofing. Hollow doors well they work as good as drums and will probably amplify noise. Glass I do not think will be any better (I could be wrong.).
Solid doors are better.  

Check this site out for more details.
http://www.trustile.com/technical-information/understanding-stc-ratings