Vacuum-deposited amorphous phthalein films

Vacuum-deposited phthalein films in the amorphous state were studied. These films are transparent in the visible region and stable at room temperature. The crystallization energy for the deposited film, determined with a differential scanning calorimeter, is about 1.5 eV. The amorphous states of these deposited phthalein films were preserved by high energy barriers for crystallization. The lifetimes of the amorphous states of the deposited phthalein films are estimated to be several years at room temperature. These amorphous organic films are expected to have an optical use, because of their good optical transparencies and stabilities.