FTIR STUDIES OF POLYIMIDES .2. FACTORS AFFECTING QUANTITATIVE MEASUREMENT

Measurement of imidization by IR spectroscopy has frequently been reported to give results that are either insensitive to changes in the latter part of the cure or in conflict with observations by other methods. However, an analysis of imide formation using the 1370 cm-1 band (C-N stretch) in conjunction with the 1500 cm-1 aromatic band as an internal standard appears capable of giving precise, internally consistent measurements for the most commonly used polyimide structures, for samples that are measured in transmission. Measurements of imide content in ultrathin films by grazing incidence reflection spectroscopy appear to be at least semiquantitative.