Fiberglass
Fiberglass is made from thin filaments of glass. It is flexible, unlike most other forms of glass. Thin flexible glass is available from commercial vendors[1]. It might make an interesting material for Martian greenhouses, if it proves to be fabricable on Mars.
Fiber Reinforced Polymers
Natural or synthetic polymers are often combined with fiberglass to create a strong, yet lightweight, composite material. This material is often referred to as fiberglass, though technically it is a fiber reinforced polymer (FRP).
Production
Fiberglass can be produced on Mars from molten glass.