NOVELTY - Photovoltaic module comprises: a photovoltaic semiconductor; and at least one layer containing a synthetic polymer and a hindered amine light stabilizer comprising substituted piperidine compounds (I) or substituted (1,3,5)triazine compounds (II).    USE - The photovoltaic module is useful for stabilizing a synthetic polymer and for peroxide induced crosslinking of a synthetic polymer (all claimed).    ADVANTAGE - The photovoltaic module: provides stabilized polymeric encapsulant; has a structure, which is supported and provides protection against external mechanical stress, electrical isolation against the environment, and transferred away the thermal energy from the circuit; and provides the layer or layers, which have excellent optical properties e.g. optical transparency, mechanical strength and thermal resistance which can endure the high temperature which is applied during processes.    DETAILED DESCRIPTION - Photovoltaic module comprises: a photovoltaic semiconductor; and at least one layer containing a synthetic polymer and a hindered amine light stabilizer comprising substituted piperidine compounds of formula (I) or substituted (1,3,5)triazine compounds of formula (II).    Z1, Z2 = 1-18C alkyl, 5-7C cycloalkyl or 2-12C alkyl (substituted with OH);    Y1 = O or N-R1;    m = 1, 2 or 6;    q = 2-20;    X1 = substituted piperidine moieties of formula (IIa);    R1 = H, 1-8C alkyl or 5-7C cycloalkyl; and either    R2-R5 = H, 1-8C alkyl, 5-7C cycloalkyl or 2-12C alkyl (substituted with OH); or    R2R3N, R4R5N = pyrrolidine, piperidine or morpholine.    Provided that: when m is 1, Y1 is O and A is 1-19C alkylcarbonyl; when m is 2, Y1 is O and A is -C(=O)-, or Y1 is N-R1 and A is substituted (1,3,5)triazine moiety of formula (Ib); and when m is 6, Y1 is N-R1 and A is N,N'-bis-(4,6-diyl-(1,3,5)triazin-2-yl)-N-(2-(3-(4,6-diyl-(1,3,5)triazin-2-ylamino)-propylamino)-ethyl)-propane-1,3-diamine moiety. INDEPENDENT CLAIMS are also included for:    (1) stabilizing a synthetic polymer in at least one layers present in a photovoltaic module possessing a photovoltaic semiconductor, which comprises the addition of (I) or (II) into the synthetic polymer; and    (2) a method for peroxide induced crosslinking of a synthetic polymer in at least one layers present in a photovoltaic module possessing a photovoltaic semiconductor, which comprises the addition of (I) or (II) and an organic peroxide compound into the synthetic polymer.