NOVELTY - Polymer compositions comprise: (a) at least 10 wt%, based on the combined weight of components (a) and (b), of a polymer selected from polyarylene polyethers having recurring units of -(-X1-(E-(A)o)n-(X2)r-(E'-(A')p)m-)-, polyimides comprising recurring units including at least one or more aromatic ring and one or more imide groups as such or in their amic acid form -(C=O)-N-(C=O)-, -(C=O)-OH, or -(C=O)-NH- or a halogenated polymer; and (b) 0.1 wt% to 100 wt%, based on the weight of (a), of at least one core/shell particle.    USE - The polymer compositions are useful for preparing photovoltaic module (claimed).    ADVANTAGE - The invention provides polymer compositions comprising polymer and core/shell particle with improved properties.    DETAILED DESCRIPTION - Polymer compositions comprise: (a) at least 10 wt%, based on the combined weight of components (a) and (b), of a polymer selected from polyarylene polyethers having recurring units of -(-X1-(E-(A)o)n-(X2)r-(E'-(A')p)m-)-, polyimides comprising recurring units including at least one or more aromatic ring and one or more imide groups as such or in their amic acid form -(C=O)-N-(C=O)-, -(C=O)-OH, or -(C=O)-NH- or a halogenated polymer; and (b) 0.1 wt% to 100 wt%, based on the weight of (a), of at least one core/shell particle comprising (b1) at least one core comprising at least one inorganic compound C1 comprising at least one metal M1, and (b2) a shell comprising at least one inorganic compound C2 comprising at least one metal M2 where the compounds C1 are selected from oxides, oxyfluorides, oxyhydroxyfluorides and mixtures, the compounds C2 are, independently from the compounds C1, selected from oxides, fluorides, oxyfluorides, oxyhydroxyfluorides and its mixtures, the metal M1 is selected from Zn, Ti, Zr, Ce or its mixtures, the metal M2 is selected from Si, Mg, Ca, Sr and its mixtures, the molar ratio of the metal M1 in the core to the metal M2 in the shell is in the range of from 0.1:1 to 1.7:1, and the average particle diameter of the core shell particles is less than or equal to 300 nm.    X1 and X2=-O- or -S-;    E and E'=the same or different and represent arylene groups containing 6 to 24 carbon atoms;    A and A'=the same or different and represent a mono-substituted 1,4-phenylene of -B-C6H4-;    B=O, S, CH2, C(CH3)2, C(CF3)2, SO2 or CO;    n and m=independently an integer of from 1 to 3;    o and p=0, 1 or 2; and    r=0 or 1.    An INDEPENDENT CLAIM is a photovoltaic module comprising the polymer composition.