Abstract: A polymer composition for impregnating a high temperature superconductor (HTS) coil, the composition comprising: a polymer resin, a plurality of particles of a first filler material, and a plurality of particles of a second filler material; wherein the median particle size of the second filler material is less than the median particle size of the first filler material. The polymer composition may be used to prepare a polymer impregnated HTS coil having a predetermined turn-to-turn spacing. A property of the polymer composition may also be modified, for example, the coefficient of thermal contraction and/or resistivity of the composition. Also disclosed is a polymer impregnated HTS coil and a method for preparing the coil.