Norbornene-alt-Maleic Anhydride polymers have been recently introduced to fulfill the transparency and plasma durability requirements demanded for 193 nm lithography single layer resist system. Very few information exist in the literature on these new materials. This paper investigates the properties of some representative polymers of this family, and tries to draw general rules. The investigation of the physico-chemical properties requires advanced characterization techniques such as modulated temperature DSC. The copolymers of N/MA and Methacrylate monomers appear to show interesting Tg switch effect. Additional information have been obtained with the implementation of Dielectric Analysis. The high rigidity of these polymers can explain their high resolution performance reported in the literature. More generally N/MA polymers exhibit unusual properties that raise new questions on the structure of the resist film and on the process mechanisms involved.