Effect of post heat-treatment on spectral shifts photopolymer reflection holograms and its use for creating color holograms

The effect of post heat-treatment on the spectral properties of photopolymer reflection holograms scheme has been studied. It has been established that holograms with protective film retain a high diffraction efficiency of $\sim$ 90% and do not have additional shrinkage during heat treatment for several days at a temperature of 80–90$^\circ$C. The holograms without a protective film, removed after exposition, when heated in the temperature range of 40–110$^\circ$C, show effective shrinkage up to 17% without compromising diffraction efficiency. Addiction the degree of shrinkage from the time of keeping the hologram at a given temperature is described by the function biexponential growth with saturation. The parameters of the approximating function are calculated. The characteristic shrinkage times in the temperature range of 40–110$^\circ$C decrease from hours to minutes for fast components and from tens of days to tens of minutes for the slow component. Effect large shift of spectral response was used to create color-separated holograms. Color-separated holograms were obtained in two ways: two-layer version with shrinkage of one of the layers, single-layer version using photoresistive pattern and subsequent shrinkage.