The photopolymers with a hydrophilic matrix as poly(vinyl alcohol), PVA, are versatile holographic recording materials
in hologram recording experiments. They use water as solvent and they can be made in layers with several thickness.
One of the photopolymers more used is composed of acrylamide as polymerizable monomer, PVA and water as binder.
The pair: triethanolamine, TEA, and the dye yellowish eosin, YE, is widely used as initiator system due to its high
sensitivity and efficiency. TEA is the radical initiator more used with dyes derived from fluorescein as YE because they
can generate a radical by redox reaction under dye excitation by light. The dye is bleached in this process because is
decomposed in the photoinitiation reaction. The ethylenediaminetetraacetic acid EDTA has a molecular structure very
similar to TEA and therefore could replace it in this kind of photopolymers.
The 4,4' azo-bis-(4-cyanopentanoic acid), ACPA, is a radical initiator that is soluble in water and usually used in
polymerizations in solution with thermal initiation. In this work, we use EDTA and ACPA in order to check their
properties as radical initiator in the photochemical reaction that takes place inside the photopolymer while a hologram is
being recorded. We will compare the results obtained with those derived from TEA and will evaluate the possibilities for