What is the difference between Acrylic and Glass?

Cell cast acrylic and polished optical glass are the two best optical filter materials. Acrylic is a polymer which allow for easy fabrication, small to large sizes, great laser protection, formulation at any thickness from 1mm to 6+mm, and reasonable laser damage thresholds combined with a low cost per square foot. Glass has excellent transmission, optical properties and laser damage thresholds. It is difficult to re-engineer in different thicknesses or create new filter designs. It is multiple times more expensive than acrylic per unit area, and available in small sizes, making it most useful in small view ports, or eyewear.