Relaxation of poled order is measured by following the decay of the second harmonic generation signal in a variety of non linear optical polymers with T g s varying from 90°C to 225°C. The non linear chromophores have been incorporated into the polymer hosts either as dissolved guests or by covalent attachment to the polymer backbone as a side chain. In the guest host case, it is shown that there is a strong correlation between the characteristic poled order relaxation time at a particular temperature and the T g of the guest host system. The poled order decay in side chain polymers is consistent with this universal relationship over a limited temperature range just below T g but deviates from it at lower temperatures