Organic-inorganic perovskites have recently been shown to be potentially efficient and inexpensive photovoltaics. These materials undergo a series of structural transitions and it is our aim to understand the dynamics driving these transitions. This proposal requests time to study the dynamics driving the structural transitions in CH3NH3PbBr3 using a combination of high resolution spectroscopy on IRIS, MAPS, and the complementary selection rules of Raman spectroscopy. This proposal is directed towards IRIS but is paired with a similar proposal on MAPS.