We report persistent spectral hole burning (PSHB) in metal-free tetraphenylporphyrin (TPP) doped polymethylmethacrylate (PMMA) core fiber (diameter : 125-600 mu m, length : 10-55 mm) via the proton tautomerization of TPP. Fabrication of PSHB materials with fiber structure offers an effective way to satisfy one of the vital requirements in PSHB materials development - PSHB materials need to contain sufficient photoreactive guest molecules to make it possible to burn many holes within a single focused spot - in order to realize the optimum total storage density in a frequency domain optical data storage scheme. Advantages as well as limitations of the fiber PSHB materials are discussed having in view the application for future high density optical data storage.