Method for operating a switchable stack and said switchable stack

A method for operating a switchable stack, comprising two transparent dielectric substrates, each of said two transparent dielectric substrates having one electrode layer and one alignment layer over the electrode layer, and, located between the alignment layers, a liquid crystals based layer of a material comprising nematic liquid crystals and ions,

• the method comprising successively:
• an off stage, in which no voltage is applied to the switchable stack and the switchable stack is in a transparent state,
• a transitory on stage, with application to the switchable stack, for a duration T1, of alternating voltage U1 defined by a first root mean square voltage Ur1 with a given frequency f1 or of continuous voltage having said value Ur1, the switchable stack passing from the transparent state to a first scattering state with first haze H1 during the transitory on stage,
• an operation stage, with application to the switchable stack of second alternating voltage U2 defined by a second root mean square voltage Ur2 with a given frequency f2, second root mean square voltage Ur2 being lower than first root mean square voltage Ur1, and the switchable stack passing from the first scattering state to a second scattering state defined by a second haze H2 greater or equal to 80%, during the operation stage.