Tell us about yourself!
To back up colin.bravi's point - using any lightweigh (aluminum, magnesium, titanium, etc). metallic alloy would give you a larger coefficient. There does exist an alloy, Invar, which has a coefficient of thermal expansion that is half of borosilicate glass. However, it's density is ~8 g/cm^3 as opposed to ~2.5 g/cm^3 for borosilicate.