Persistent spectral hole burning (PSHB) was observed in SrZrO3:Pr3+ ba
sed oxides. Holes were observed only in samples which contain protons
or deuterons. The speed of hole growth and hole filling for the sample
s which contain protons were faster than that for the samples which co
ntain deuterons. It was found that the mechanism for this hole burning
is a photo-physical process, that is, a light induced tunnelling moti
on of protons contained in the sample.