Plasma-enhanced chemical vapor deposition of SiO2 at temperatures below 300 degrees C was used in conjunction with rapid thermal annealing for quantum well intermixing. Variable blue shifts of up to similar to 200 meV were observed while still maintaining clearly resolved exitonic behavior. The energy shifts were similar for capping layers deposited below 200 degrees C, which were significantly higher than those obtained for SiO2 layers deposited at 300 degrees C. We demonstrate that the increased porosity of SiO2 capping layers deposited below 200 degrees C is responsible for the enhanced intermixing. The evidence for porosity-enhanced intermixing was obtained from spectroscopic ellipsometry, Fourier transform infrared spectroscopy, and P-etch rate measurements.