Spring :
Spring is an open-source lightweight framework that allows Java EE 7 developers to build simple, reliable, and scalable enterprise applications. This framework uses various techniques such as Aspect-Oriented Programming (AOP), Plain Old Java Object (POJO), and dependency injection (DI), to develop enterprise applications
Spring Boot :
Spring Boot is built on top of the conventional spring framework. So, it provides all the features of spring and is yet easier to use than spring. Spring Boot is a microservice-based framework and making a production-ready application in very less time.
In Spring Boot everything is auto-configured. We just need to use proper configuration for utilizing a particular functionality. Spring Boot is very useful if we want to develop REST API
Spring boot can use other frameworks other than Spring, like Jersey