a method for measuring or predicting a property of a porous material while curing , the porous material including therein a liquid which undergoes metamorphosis and which is present in the porous material in different phases during curing , the method including the steps of performing a low frequency , spin - echo nuclear magnetic resonance measurement of each phase of the liquid , and correlating the nmr measurement , or extrapolating the property , in accordance with a predetermined relationship between the property and the nmr measurement .