AbstractThe paper presents the results of a study of syndiotactic polymethyl methacrylate with a molecular weight of 107 g/mol, synthesized by the method of ionic polymerization with radiation initiation. Changes in the chemical structure of the polymer material were analyzed by means of IR spectroscopy, differential thermal analysis, and gel permeation chromatography. The process of weight loss during thermal decomposition of the initial polymer can be divided into three stages: low-temperature, medium-temperature, and high-temperature ones. After exposure of the polymer even to minimum doses of ionizing radiation, there is no pronounced thermal effect of polymer melting. A scatter in the molecular sizes was found, as well as a relatively rapid decrease in the molecular weight under the action of X-rays in the dose range of up to 100 J/cm3. Polydispersity at low doses is approximately 3.5 times higher than that at doses on the order of 10 kJ/cm3. The achieved rate of latent image development was approximately five times compared with the polymer with a molecular weight of 106 g/mol under standard conditions. The contrast was 3.4. Microstructuring was performed by the X-ray lithography method on the VEPP-3 source with the use of synchrotron X-rays. The resulting microstructures are up to 5 µm high and about 2 µm in diameter.