Abstract: The present invention relates to a temperature-time indicator system which allows monitoring the maintenance of the cold chain in frozen or refrigerated substances based on irreversible color changes, comprising a layer with a solution of ascorbic acid and a layer with a solution of at least one base, wherein the solution of ascorbic acid does not mix with the solution of at least one base unless the temperature reaches a pre-determined threshold. The invention also relates to a method using said system.

Abstract: The invention relates to a device comprising one left electrochromic filter (3) and one right electrochromic filter (4) controlled by an electronic device (12). Said electronic device has means for controlling at least one filtering parameter, said means being actuatable by the user and programmed by a professional ophthalmologist, or a combination of the two. The aim of the invention is to provide variable filtering for the vision of a user of the device.

Abstract: The invention relates to electrochromic compositions comprising: (a) a viologen derivative of formula (I) (b) an electron mediator; (c) a polymer compound of formula (II) (d) a plasticizer of formula (III): and (e) a mixture of at least two miscible solvents which dissolve components (a) to (d) at room temperature, at least one of them being a solvent with a high boiling point. Said electrochromic compositions can be formulated and applied at room temperature, therefore they allow preparing electrochromic devices with heat-sensitive substrates, particularly with fully plastic substrates, with a high degree of transparency and with a high optical contrast.