Organic-inorganic hybrid solids have been prepared using sol-gel process. The sol-gel technique offers a room temperature attractive approach for introducing molecules into amorphous inorganic materials. Molecular doped inorganic or hybrid (organic-inorganic) xerogels are revealed to be suitable for high temperature PSHB. With molecules covalently grafted or chemically bonded to the inorganic network, a maximum temperature of 120 K has been achieved. Temperature cycling experiments reveals the importance of spectral diffusion in these systems. Spectral diffusion appears to be the most important difficulty to overcome.