I'm not a pilot so know nothing about canopy design, or materials used, but when I was a paramedic I used to carry a spring loaded centre punch in case I ever had to smash a car window. Only ever tried it on an old abandoned car but worked well on automotive glass. Much less effort than a traditional safety hammer. Dont think I'll be able to post links or photos on here but search on google for "spring loaded centre punch" and you'll find loads...