Here is a summary of plunge-molding references to get you started:
Mike's Flying Scale Model Pages
"Moulding Your Own Cockpit Canopies"
http://www.ffscale.co.uk/page4f.htm
(thanks to Ken Pugh)
You-Tube video of Asao Shirai-san, a plastic modeler in Japan, including plunge-molding and photographing models "in flight".
"The world of wonderful plastic model"
http://www.youtube.com/watch?v=_SZQpUNJG4E
(thanks to Dave T.)
Plunge-Moulding discussion at scale-models.co.uk
http://www.scale-models.co.uk/tutorials/4447-plunge-moulding.html
"Canopy Molding Simplified"
by George White
from Pensicola Free Flight's magazine "Thermalier"
http://tpbweb.com/media/catalog/750.pdf