In general, the peaks from the glass are more intense than those from ZIF-8 because there is more IG in each sample, and their intensities do not vary greatly between samples. The latter is because, whereas the amount of ZIF-8 changes by a factor of three between samples with x = 0.1 and x = 0.3, the amount of IG only changes by (1-0.3)/(1-0.1) = 0.78.