1. A method for measuring polymer properties of samples in real time, comprising: storing a plurality of models wherein at least two of the models are useful in predicting a value of a particular property of a sample and at least one of the models is useful in identifying which of the at least two models more accurately predicts the value of the particular property; taking a series of samples of an unknown polymer material from an industrial on-line process and placing each of the samples successively in a test region; applying a base magnetic field to the sample in the test region to effect precession of nuclei of the sample; modifying the precession; receiving a resulting relaxation signal representative of a free induction decay of the nuclei of the sample; digitizing the free induction decay and analyzing it into component equations; processing the component equations with an iterative technique to derive coefficients representative of the component equations; utilizing the coefficients, or information based on the coefficients, and the at least one model in order to select one of the at least two models; utilizing the coefficients, or information based on the coefficients, and the selected one of the at least two models in order to predict the value of the particular property; and discarding the sample from the test region.