Beschreibung:
<jats:p>The efficiency of hole formation and the thermal stability of holes burnt at 4.2 K with 0.36 or 3.6 mW/cm2 helium-neon laser are studied for tetraphenylporphin (TPP) in phenoxy resin (aromatic polyhydroxyether, PhR) as well as in poly(methyl methacrylate) (PMMA). The efficiency of hole formation for TPP in PhR at 4.2 and 30 K is much higher than that in PMMA and the hole depth reaches more than 30% of initial absorbance. The purification by reprecipitation of the matrix polymer and the annealing of the sample films improve the efficiency. Our system of TPP in PhR is the first system in which the hole was detected even at liquid-nitrogen temperature (80 K) after 30 min annealing at the temperature. Partial recovery of the hole cooled again to 4.2 K was observed after holding the sample for 30 min at 120 K.</jats:p>