The IR edge absorption of the important pure components of ZrF4-based glasses, including two previously uncharacterized components(ZrF4 and AlF3), has been measured. Values of the glass IR edge absorption coefficients have been calculated from these results, assuming additivity, and are compared with experimental glass absorption coefficients. The calculated ${alpha}$ values are about a factor of two lower than the experimental values for ZrF4-based glasses, and the ZrF4 makes the largest contribution to the calculated ${alpha}$ value.