We have prepared and characterized PMMA films doped with three new Pt-containing acetylides for second-order optical nonlinearity. The noncentrosymmetric order of chromophores in the matrix was achieved through corona poling and monitored in situ with measurements of second-harmonic generation. The values of second-harmonic coefficient are of the same order as in DR1-doped films with the advantage of a lower absorption in the visible region. The data of the orientational decay confirm the relaxation dynamics of doped PMMA. © 1999 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint.