Macroreticular polymers and copolymers based on poly(ethylene glycol dimethacrylate esters) possessing a permanent porosity (white opaque beads, 40-60% porosity, 354 m(2)/g, the apparent density less than 1.060 g/mL, etc.) were prepared. The influence of the porogen thermodynamic quality and its weight fraction used in the polymerization mixture on the bead structure was also studied. The porous structure of the matrices was investigated and proved by SEM analyses, the N-2 adsorption (BET) method, etc. The thermal degradation mechanism of the macroreticular beads based on dimethacrylate esters shows that the thermal stability of samples depends on the monomer structure, i.e., the chain length between the two vinyl groups.