An optical element including a first optical layer, a second optical layer, and a transparent base material, the first optical layer being disposed between the second optical layer and the transparent base material and a diffraction grating being disposed at the interface between the first optical layer and the second optical layer, wherein the refractive index of the d-line of the second optical layer is higher than the refractive index of the d-line of the first optical layer, the Abbe number of the second optical layer is higher than the Abbe number of the first optical layer, the first optical layer is composed of a first resin and inorganic particles dispersed in the first optical layer, and the second optical layer is composed of a second resin having a modulus of elasticity of 0.1 GPa or more and 3.0 GPa or less at 22° C. or higher and 24° C. or lower.

An optical element including a first optical layer, a second optical layer, and a transparent base material, the first optical layer being disposed between the second optical layer and the transparent base material and a diffraction grating being disposed at the interface between the first optical layer and the second optical layer, wherein the refractive index of the d-line of the second optical layer is higher than the refractive index of the d-line of the first optical layer, the Abbe number of the second optical layer is higher than the Abbe number of the first optical layer, the first optical layer is composed of a first resin and inorganic particles dispersed in the first optical layer, and the second optical layer is composed of a second resin having a modulus of elasticity of 0.1 GPa or more and 3.0 GPa or less at 22° C. or higher and 24° C. or lower.

Polythioether prepolymers that have a low nucleation temperature. The symmetry of the polythioether prepolymers is modified by including pendent groups extending from the backbone of the polythioether prepolymer chain and/or the symmetry is modified by including segments having a different number of —C(R).sub.2— groups between heteroatoms. The polythioether prepolymers are stable at low temperature storage conditions for an extended period of time. Compositions prepared using the low nucleation temperature polythioether prepolymers are useful as sealants.

Polythioether prepolymers that have a low nucleation temperature. The symmetry of the polythioether prepolymers is modified by including pendent groups extending from the backbone of the polythioether prepolymer chain and/or the symmetry is modified by including segments having a different number of —C(R).sub.2— groups between heteroatoms. The polythioether prepolymers are stable at low temperature storage conditions for an extended period of time. Compositions prepared using the low nucleation temperature polythioether prepolymers are useful as sealants.

Polythioether prepolymers that have a low nucleation temperature are disclosed. The polythioether prepolymers are stable at low temperature storage conditions for an extended period of time. Compositions prepared using the low nucleation temperature polythioether prepolymers are useful as sealants.

Polythioether prepolymers that have a low nucleation temperature are disclosed. The polythioether prepolymers are stable at low temperature storage conditions for an extended period of time. Compositions prepared using the low nucleation temperature polythioether prepolymers are useful as sealants.

In one aspect, the disclosure relates to compositions comprising semicrystalline, linear photopolymers that possesses extraordinary mechanical properties for application in 3D printing. The photopolymers are rapidly fabricated using low viscosity liquids at ambient conditions.

In one aspect, the disclosure relates to compositions comprising semicrystalline, linear photopolymers that possesses extraordinary mechanical properties for application in 3D printing. The photopolymers are rapidly fabricated using low viscosity liquids at ambient conditions.

Urethane/urea-containing bis(alkenyl) ethers can be incorporated into the backbone of polythioether prepolymers and can be used as curing agents in thiol-terminated polythioether prepolymer compositions. Cured sealants prepared using compositions containing urethane/urea-containing bis(alkenyl) ether-containing polythioether prepolymers and/or urethane/urea-containing bis(alkenyl) ether curing agents exhibit improved physical properties suitable for use in aerospace sealant applications.

Urethane/urea-containing bis(alkenyl) ethers can be incorporated into the backbone of polythioether prepolymers and can be used as curing agents in thiol-terminated polythioether prepolymer compositions. Cured sealants prepared using compositions containing urethane/urea-containing bis(alkenyl) ether-containing polythioether prepolymers and/or urethane/urea-containing bis(alkenyl) ether curing agents exhibit improved physical properties suitable for use in aerospace sealant applications.