A numerical model concerning the phase transition and temperature distribution of matrix media around plasmonic nanoparticle assemblies under illumination of monochromatic light is investigated. The critical intensity of incident light for isolated nanosphere, nanodisk, and nanorod to melting the surrounding ice is obtained. For nanospheres and nanodisk dimers, enhancement of photothermal conversion (PTC) is observed. Besides, the phase transition of matrix media is not only influenced by FTC, but also the configuration of nanoparticle assemblies. In particular, we demonstrate that for nanorod dimers arranged end-to-end and side-to-side, the dissipation of light for two nanorods are the same in every polarization angles. The change of polarization angle only influence the overall light-to-heat conversion of the dimer. However, for L geometry nanorod dimer, the dissipation of light are different for the two nanorods. This present a way to manipulate and precisely control of temperature distribution and phase transition in nanoscale by tuning the light polarization angles. (C) 2018 Elsevier Ltd. All rights reserved.